Atomic Number

Question 2

Give the atomic number.

Answer 2

Hydrogen is the lightest and most abundant element.

It is a colorless, odorless gas used in making ammonia and in fuel cells.

Question 3

Give the atomic number.

Answer 3

Helium is a low-reactivity noble gas and the second lightest element.

It is used as a coolant in nuclear reactors and MRI machines.

A mix of 80% helium and 20% oxygen creates an artificial atmosphere for deep-sea divers.

Question 4

Give the atomic number.

Answer 4

Lithium is a soft, silver-white metal used in ceramics, glass, and lithium-ion batteries.

It is also used as a mood stabilizer for treating psychiatric conditions like bipolar disorder, though it can have side effects and its mechanism in the brain is not fully understood.

Question 5

Give the atomic number.

Answer 5

Beryllium is a rare, toxic metal that can cause berylliosis, a lung inflammation, if inhaled.

Known for its stiffness, light weight, and high-temperature tolerance, it is commonly used in aerospace applications.

Question 6

Give the atomic number.

Answer 6

Boron is a metalloid that is used as a neutron absorber in nuclear reactors.

It is used in the production of fire-retardant materials, and is an essential mineral component of plant cell walls.

Question 7

Give the atomic number.

Answer 7

Carbon is a key component in the production of steel, graphite, and carbon fiber materials.

It is present in the atmosphere of many planets as carbon dioxide most commonly.

Question 8

Give the atomic number.

Answer 8

Nitrogen is used to produce ammonia, fertilizer, and as a cooling agent in the food industry.

The Nitrogen Cycle is a crucial process that transfers nitrogen between the atmosphere and organic compounds, supporting life.

Question 9

Give the atomic number.

Answer 9

Oxygen, which makes up about 21% of Earth’s atmosphere, first appeared about 2 billion years ago due to photosynthesizing organisms. It is used in producing rocket fuel, welding, and metal cutting.

Question 10

Give the atomic number.

Answer 10

Fluorine is the most reactive element in the periodic table.

It has various applications, including in the production of fluorocarbons, rocket fuels, and in the manufacturing of toothpaste.

Question 11

Give the atomic number.

Answer 11

Neon is a colorless, odorless noble gas used in lighting, cryogenics, and diagnostic imaging in the medical field.

Question 12

Give the atomic number.

Answer 12

Sodium is used in making soap, paper, semiconductors, flat glass, and as a heat exchanger in nuclear reactors.

Question 13

Give the atomic number.

Answer 13

Magnesium is a soft, silvery-white metal essential for plant and animal life. It is used in aluminum alloys, fireworks, water treatment, and as a key component of Grignard reagents in the chemical industry.

Question 14

Give the atomic number.

(or Aluminum)

Answer 14

Aluminium is the third most abundant element in the Earth’s crust.

It is commonly used in the production of cookware, foils, and in the automotive industry for lightweight parts.

Question 15

Give the atomic number.

Answer 15

Silicon is a metalloid essential for producing semiconductors, silicone polymers, and glass.

It is commonly used in solar cells, integrated circuits, and computer chips.

Question 16

Give the atomic number.

Answer 16

Phosphorus is used in fertilizers, pesticides, and semiconductor manufacturing. It is an essential mineral for all living organisms and a key component of lipids in animal cell membranes.

Question 17

Give the atomic number.

(or Sulfur)

Answer 17

Sulfur is used in fertilizers, paper production, and gunpowder manufacturing.

It is also commonly used to produce chemicals like sulfuric acid, as a bleaching agent, and in rubber manufacturing.

Question 18

Give the atomic number.

Answer 18

Chlorine is a highly reactive, greenish-yellow gas essential for human health.

It is commonly used as a disinfectant in swimming pool water, in paper manufacturing, and in solvent production.

Question 19

Give the atomic number.

Answer 19

Argon is used in incandescent light bulbs, welding, diagnostic imaging, and as insulation between panes of double-glazed windows.

Question 20

Give the atomic number.

Answer 20

On average, we consume up to 7g of potassium daily and store about 140g in our cells.

Potassium is a soft, silvery alkali metal that reacts violently with water.
It is used in producing fertilizers, gunpowder, and as a coolant in nuclear reactors.

Question 21

Give the atomic number.

Answer 21

Calcium is a soft, gray alkaline earth metal essential for plant and animal life.

It is used in cement, mortar, dairy supplements, building materials, water treatment as calcium chloride, and as a reducing agent in producing metals like thorium and uranium.

Question 22

Give the atomic number.

Answer 22

Scandium is a silvery-white transition metal used in high-intensity lamps, aerospace alloys, and the petrochemical industry.

It is also used in aluminum alloys, fuel cells, and as a tracer in oil refineries and natural gas processing.

Question 23

Give the atomic number.

Answer 23

Titanium is a strong, lightweight transition metal with excellent corrosion resistance and high strength.

It is used in aerospace applications, medical devices, orthopedic implants, sporting goods, and as a pigment in paint and plastics in its titanium oxide form.

Question 24

Give the atomic number.

Answer 24

Vanadium is a silvery-gray transition metal.

It is used in the production of steel alloys, some batteries, and as a catalyst in the chemical industry.
Vanadium is used in the production of superconducting magnets and as a corrosion-resistant additive in various alloys.

Question 25

Give the atomic number.

Answer 25

Chromium is a hard, lustrous transition metal used in stainless steel, chrome plating, and as a coloring agent in glass and ceramics.

It is also used in producing chrome pigments and as a catalyst in its chromium oxide form for various chemical reactions.

Question 26

# Give the atomic number.

Answer 26

## Footnote Manganese is a gray-white transition metal essential for steel production, batteries, fertilizers, and pigments. It is also used in ceramics, as a catalyst in chemical reactions, and as a cofactor for many enzymes.

Question 27

# Give the atomic number.

Answer 27

## Footnote Iron is a transition metal and the most commonly used metal in construction, vehicles, and various alloys. It is used in producing steel, magnets, and as a catalyst in the Haber process for ammonia synthesis.

Question 28

# Give the atomic number.

Answer 28

## Footnote Cobalt is a hard, lustrous transition metal used in producing alloys, magnets, and as a pigment in ceramics and glass. It is also used in superalloys for jet engines, rechargeable batteries, some cancer treatments in its radioactive form, and as a component in vitamin B12.

Question 29

# Give the atomic number.

Answer 29

## Footnote Nickel is a silvery-white transition metal used in producing stainless steel, coins, and as a catalyst in hydrogenation reactions. It is essential for the growth of some plants, and navy beans contain a surprisingly high amount of it.

Question 30

# Give the atomic number.

Answer 30

## Footnote Copper is a soft, malleable transition metal that is an excellent conductor of electricity, used in electrical wiring, plumbing, and various alloys. It was the first metal utilized by humans in alloy form with tin, marking the beginning of the Bronze Age.

Question 31

# Give the atomic number.

Answer 31

## Footnote Zinc is a bluish-white transition metal used in producing galvanized steel, batteries, and as a micronutrient in the human body. Excessive amounts of zinc may be carcinogenic, and newly formed zinc (II) oxide can cause a condition known as 'oxide shakes' or 'zinc chills'.

Question 32

# Give the atomic number.

Answer 32

## Footnote Gallium is a soft, silvery post-transition metal with a low melting point. It is used in semiconductors, LEDs, and as a coolant in nuclear reactors. Gallium is also used in producing mirrors and as an alloying agent to lower the melting point of other metals.

Question 33

# Give the atomic number.

Answer 33

## Footnote Germanium is a lustrous, hard metalloid used in fiber optics and as a catalyst in polymerization reactions, such as producing PET bottles. It is also used as an alloying agent in some types of steel and as a semiconductor.

Question 34

# Give the atomic number.

Answer 34

## Footnote Arsenic is a gray, brittle metalloid that is highly toxic and sometimes used in regulated rat poisons and insecticides. It is also used in producing alloys, wood preservatives, and as a doping agent in semiconductor materials.

Question 35

# Give the atomic number.

Answer 35

## Footnote Selenium is a metalloid element that is an essential trace element for humans and animals, but in excess, it can be toxic, carcinogenic, and teratogenic for humans. It is used in the production of glass, pigments, and has photovoltaic properties, enabling it to convert light energy into electrical energy.

Question 36

# Give the atomic number.

Answer 36

## Footnote Bromine is a reddish-brown halogen liquid previously used as a flame retardant, though this application has been phased out in the USA due to toxicity concerns. It is now used in the production of dyes, as a disinfectant, and in various pharmaceuticals.

Question 37

# Give the atomic number.

Answer 37

## Footnote Krypton is a colorless, odorless noble gas used in some lighting, lasers, and as an insulating gas in windows and double glazing. While it generally does not react with other elements under normal conditions, krypton is reactive enough to form some compounds, unlike most other noble gases.

Question 38

# Give the atomic number.

Answer 38

## Footnote Rubidium is a soft, silvery-white alkali metal used in atomic clocks, as a getter in vacuum tubes, and in producing specialty glasses. It is highly reactive, easily combines with other elements, and is mostly used in research due to its tendency to ignite in air and react violently with water.

Question 39

# Give the atomic number.

Answer 39

## Footnote Strontium is a soft, silvery alkaline-earth metal used in fireworks, flares, and as a colorant in pyrotechnics. Strontium-90, a radioactive isotope with a half-life of 28 years, is present in nuclear fallout. If absorbed by bone tissue, it can destroy marrow and be carcinogenic.

Question 40

# Give the atomic number.

Answer 40

## Footnote Yttrium is a silvery transition metal used in producing phosphors for fluorescent lamps, lasers, and superconductors. Yttrium-90 has medical applications, including the treatment of liver cancer.

Question 41

# Give the atomic number.

Answer 41

## Footnote Zirconium is a gray-white transition metal used in nuclear reactor components, alloys, and as a gemstone substitute. It is non-corrosive and serves as a catalyst in some compound forms during organic synthesis.

Question 42

# Give the atomic number.

Answer 42

## Footnote Niobium is a soft, gray transition metal used in superalloys for jet engines, superconducting magnets, and stainless steel production. It is also used in MRI equipment and NMR scanners.

Question 43

# Give the atomic number.

Answer 43

## Footnote Molybdenum is a silvery transition metal used in producing high-strength alloys, catalytic converters, and as a corrosion-resistant material. It is also a key component for many enzymes in nature, such as the bacterial molybdenum nitrogenase, which is involved in nitrogen fixation.

Question 44

# Give the atomic number.

Answer 44

## Footnote Technetium is the lightest element with no stable isotopes, as their half-lives are short relative to the age of the Earth. It is used in medical imaging and research. It does not occur naturally and is produced as a fission product from uranium nuclear fuel.

Question 45

# Give the atomic number.

Answer 45

## Footnote Ruthenium is a shiny, silvery, and rare transition metal used in the production of electrical contacts, as a catalyst, and as a hardening agent. Some of its compounds are used in solar cells to convert light into electrical energy.

Question 46

# Give the atomic number.

Answer 46

## Footnote Rhodium is a rare, silvery-white metal. It is used in catalytic converters, jewelry, and mirrors. Rhodium is the rarest non-radioactive metal and is usually obtained as a byproduct of nickel and copper mining. It can also be found naturally in its pure form.

Question 47

# Give the atomic number.

Answer 47

## Footnote Palladium is a rare, shiny metal. It is used in catalytic converters, electronics, and as a catalyst in chemical reactions. Palladium is also used to make 'white gold,' an alloy.

Question 48

# Give the atomic number.

Answer 48

## Footnote Silver is a shiny metal. It is used in jewelry, coins, photography, electronics, and various industrial applications. Due to its antibacterial properties, silver nanoparticles are used in clothing to prevent odors caused by bacteria.

Question 49

# Give the atomic number.

Answer 49

## Footnote Cadmium is a soft, bluish-white metal. It is highly toxic and was used in pigments, plastics, and batteries, though this use is decreasing. Cadmium is also used in nuclear reactor rods to control atomic fission by absorbing neutrons.

Question 50

# Give the atomic number.

Answer 50

## Footnote Indium is a soft, silvery metal. Most of it is used to make indium tin oxide (ITO), which is a key component in touchscreens, solar panels, and flat-screen TVs due to its electrical conductivity and transparency. In the Edo period of Japan (1603-1867), indium was extensively used to dye fabrics as an alternative to indigo for cotton.

Question 51

# Give the atomic number.

Answer 51

## Footnote Tin is a silvery-white metal. It is used to make solder with lead, cans, and as a protective coating for other metals. Tin slowly turns to powder at temperatures below 13°C.

Question 52

# Give the atomic number.

Answer 52

## Footnote Antimony is a brittle, silvery-white metalloid. It is used in flame retardants, alloys, and lead-acid batteries. Despite its toxicity, the ancient Egyptians used antimony sulfide for mascara.

Question 53

# Give the atomic number.

Answer 53

## Footnote Tellurium is a brittle, silver-white metalloid. It is used in solar cells, thermoelectric devices, and as an additive in steel. Due to its toxicity, exposure to tellurium can cause a garlic-like odor in the mouth, known as 'tellurium breath'.

Question 54

# Give the atomic number.

Answer 54

## Footnote Iodine is a bluish-black halogen. It is used in pharmaceuticals, dyes, and as a disinfectant. Louis Daguerre popularized the use of iodine in photography, creating images on metal plates called daguerreotypes.

Question 55

# Give the atomic number.

Answer 55

## Footnote Xenon is a colorless, odorless noble gas. It is used in lighting, anesthesia, and as a propellant in ion thrusters for space equipment. Xenon is also used in camera flashes and bacterial lamps for food preparation and processing.

Question 56

# Give the atomic number.

Answer 56

## Footnote Cesium is a soft, silvery-gold metal. It is used in atomic clocks, photoelectric cells, and drilling fluids. Cesium is highly reactive and explodes upon contact with water.

Question 57

# Give the atomic number.

Answer 57

## Footnote Barium is a soft, silvery alkaline-earth metal. It is used in cathode ray tubes, fireworks, and as a contrast agent in medical imaging. A "barium meal" or "barium enema" is used in medical imaging to help visualize the digestive system.

Question 58

# Give the atomic number.

Answer 58

## Footnote Lanthanum is a soft, silvery-white rare earth metal. It is used in camera lenses, catalysts, and hybrid car batteries. In the lighting industry, lanthanum is widely used in studios and cinema projections to increase brightness and produce light similar to sunlight.

Question 59

# Give the atomic number.

Answer 59

## Footnote Cerium is a soft, silvery-white rare earth metal and lanthanide. It is used in catalytic converters, self-cleaning ovens, and glass polishing (as cerium oxide). Cerium is more abundant than lead or tin and is almost as common as zinc. It is also used in lighter flints, as it produces sparks when struck, similar to iron.

Question 60

# Give the atomic number.

Answer 60

## Footnote Praseodymium is a soft, silvery rare earth metal and lanthanide. It is used in magnets, yellow glass, and alloying agents. Praseodymium is also used in carbon-arc electrodes for studio lighting and projection, similar to other lanthanide elements.

Question 61

# Give the atomic number.

Answer 61

## Footnote Neodymium is a soft, silver-white rare earth metal and lanthanide. It is used in permanent magnets, lasers, and coloring agents for glass. Neodymium is also used in tanning booth glass to transmit UV light rays for tanning while blocking heating infrared rays.

Question 62

# Give the atomic number.

Answer 62

## Footnote Promethium is a radioactive rare earth metal and lanthanide. It has no stable isotopes and is used in self-luminous paint, nuclear batteries, and mostly for research. Promethium is used in atomic batteries that power items such as pacemakers, guided missiles, and radios.

Question 63

# Give the atomic number.

Answer 63

## Footnote Samarium is a soft, silver-white rare earth metal and lanthanide. It is used in magnets, catalysts (in some compound forms), and as a component in nuclear reactor control rods. Samarium, along with other lanthanide metals, is found in mineral deposits such as monazite and bastnaesite.

Question 64

# Give the atomic number.

Answer 64

## Footnote Europium is a soft, silver-white rare earth metal and lanthanide. It is used in phosphors for fluorescent lamps, television screens, and as a neutron absorber in nuclear reactors. In fluorescent lamps, europium helps balance the cold blue light by adding warmer red light.

Question 65

# Give the atomic number.

Answer 65

## Footnote Gadolinium is a soft, silvery rare earth metal and lanthanide. It is used in contrast agents for MRI, neutron capture therapy, and magnets. Gadolinium is also used in nuclear reactor cores due to its ability to absorb neutrons.

Question 66

# Give the atomic number.

Answer 66

## Footnote Terbium is a silvery-gray rare earth metal and lanthanide. It is used in phosphors for energy-efficient lighting, lasers, and magnets for flat-surface loudspeakers. Terbium was also a key component in the first rewritable compact discs.

Question 67

# Give the atomic number.

Answer 67

## Footnote Dysprosium is a bright, silvery rare earth metal and lanthanide. It is used in motor and generator magnets, such as those in wind turbines, leading to increased demand. Dysprosium is highly reactive with water and air, so it is rarely used in its pure form.

Question 68

# Give the atomic number.

Answer 68

## Footnote Holmium is a bright, silvery rare earth metal. It is used in the production of some magnets, and as a component in controlling chain nuclear reactions. Holmium can be found in small quantities as part of mineral deposits of monazite and bastnaesite.

Question 69

# Give the atomic number.

Answer 69

## Footnote Erbium is a soft, silvery rare earth metal and lanthanide. It is used in broadband signal amplifiers during optical communication, and as a coloring agent in glass. Erbium is seldom used in its pure form as it is highly reactive with air and water.

Question 70

# Give the atomic number.

Answer 70

## Footnote Thulium is a bright, silvery rare earth metal and lanthanide. It is used in surgical lasers, portable X-ray devices, and high-temperature superconductors. Thulium is mainly found in the mineral monazite and extracted through ion exchange and solvent extraction.

Question 71

# Give the atomic number.

Answer 71

## Footnote Ytterbium is a soft, silvery rare earth metal and lanthanide. It is used in tunable lasers, industrial catalysts, and portable atomic clocks. Ytterbium, like many other lanthanides, is commonly found in the mineral monazite.

Question 72

# Give the atomic number.

Answer 72

## Footnote Lutetium is a dense, silvery-white rare earth metal and lanthanide. It is mainly used in research and in the production of catalysts. Like other lanthanides, lutetium is most commonly sourced from the mineral monazite.

Question 73

# Give the atomic number.

Answer 73

## Footnote Hafnium is a lustrous, silvery-gray transition metal. It is used in superalloys, nuclear reactor control rods, and as an insulator in microchips. Hafnium is typically found in zirconium ores, making up about 5% of them.

Question 74

# Give the atomic number.

Answer 74

## Footnote Tantalum is a gray-blue transition metal. It is used in capacitors, surgical implants, and as a corrosion-resistant material in chemical process equipment. Tantalum is rarely found in its pure form in nature and is mostly found in the mineral columbite-tantalite.

Question 75

# Give the atomic number.

Answer 75

## Footnote Tungsten is a dense, silvery-white transition metal. It is used in high-temperature alloys, electrical contacts, and as a filament in incandescent light bulbs. Tungsten is mostly found in the ores wolframite and scheelite. Some bacterial enzymes use tungsten for reduction reactions, making it the heaviest element known to serve a biological role.

Question 76

# Give the atomic number.

Answer 76

## Footnote Rhenium is a silvery-gray transition metal. It is used in high-temperature alloys, catalysts, and X-ray machines. Rhenium is an excellent catalyst due to its high resistance to poisoning, making it valuable for hydrogenation reactions with fine chemicals.

Question 77

# Give the atomic number.

Answer 77

## Footnote Osmium is a hard, brittle, silvery transition metal. It is used in fountain pen nibs, electrical contacts, as a catalyst, and in alloys. Osmium is twice as dense as lead and is the densest of all known elements.

Question 78

# Give the atomic number.

Answer 78

## Footnote Iridium is a dense, silvery-white transition metal. It is used in spark plugs, crucibles, and the recordable layer of some DVDs. Iridium has the highest resistance to corrosion of all known elements and is nearly as unreactive as gold.

Question 79

# Give the atomic number.

Answer 79

## Footnote Platinum is a dense, silvery-white transition metal. It is used in catalytic converters, jewelry, and electrodes. Platinum is as non-corrosive as gold, and most of its commercial production comes from South Africa.

Question 80

# Give the atomic number.

Answer 80

79 ## Footnote Gold is a dense, yellow transition metal. It is highly valued for its beauty and rarity, used in jewelry, electronics, and as a monetary store of value. Gold alloys are identified by 'carat' to indicate the amount of gold present. 24-carat gold is pure gold, while lower values like 18 and 9-carat are often favored for their higher durability.

Question 81

# Give the atomic number.

Answer 81

## Footnote Mercury is a heavy, silvery transition metal. It is the only metal that is liquid at room temperature and is used in thermometers, barometers, and controversially in dental amalgams. Despite having no known biological role, mercury is present in trace amounts in all living systems, including food.

Question 82

# Give the atomic number.

Answer 82

## Footnote Thallium is a soft, bluish-white (when exposed to air) post-transition metal. It is highly toxic and was historically used in rat poisons. Thallium vapour is shown to be teratogenic (affects embryo development), carcinogenic, and can disrupt the nervous system via displacing potassium throughout the body.si

Question 83

# Give the atomic number.

Answer 83

## Footnote Lead is a dense, bluish-gray post-transition metal. It is used in the production of batteries, ammunition, and as a protective coating for electrical cables. It is obtained through a roasting process of the mineral galena, but in places such as the UK some quantities are obtained via recycling of items like pipes and batteries.

Question 84

# Give the atomic number.

Answer 84

## Footnote Bismuth is a brittle, silvery-pink post-transition metal. It is used in the production of cosmetics, pharmaceuticals, and as a component in low-melting alloys. Bismuth is naturally-occurring as a metal and found in ores like bismuthinite and bismite. Commercially though, it is often obtained through gold, copper, tin, silver and lead ore refinement.

Question 85

# Give the atomic number.

Answer 85

## Footnote Polonium is a silvery-grey, radioactive post-transition metal. It has limited uses due to its high toxicity such as a neutron source when combined with beryllium, in antistatic devices, and heat-source for space equipment. Russia is the location of all commercially produced polonium.

Question 86

# Give the atomic number.

Answer 86

## Footnote Astatine is a highly radioactive halogen element. It is one of the rarest elements on Earth and has no stable isotopes - therefore it is used only for research purposes. Astatine has no known biological role, and is highly toxic due to its radioactivity.

Question 87

# Give the atomic number.

Answer 87

## Footnote Radon is a colorless, odorless, radioactive and the heaviest-known noble gas. It is believed to have played a major role in evolution by comprising a lot of the Earth's background radiation that can give rise to genetic modifications.

Question 88

# Give the atomic number.

Answer 88

## Footnote Francium highly radioactive alkali metal. It is extremely rare and has a very short half-life, making it difficult to study. Francium has no uses due to extremely short half-life of 22 minutes.

Question 89

# Give the atomic number.

Answer 89

## Footnote Radium is a highly radioactive, soft, shiny, and silvery alkaline-earth metal. It is used in cancer treatment, as a neutron source, and was historically used in luminous paint. Radium naturally occurs in all uranium ores and can be extracted as a by-product of uranium refinement.

Question 90

# Give the atomic number.

Answer 90

## Footnote Actinium is a soft, silver-white radioactive actinide metal. It is rarely used outside of research. Actinium glows blue in the darkness due to its radioactivity exciting surrounding air particles.

Question 91

# Give the atomic number.

Answer 91

## Footnote Thorium is a radioactive actinide metal. It is used in nuclear reactors, as a catalyst in organic chemistry, and as a component in high-temperature alloys. Thorium potentially has more available energy than uranium and fossil fuels, and so countries like India and China are working towards developing nuclear power plants using it.

Question 92

# Give the atomic number.

Answer 92

## Footnote Protactinium is a silvery radioactive actinide metal. It is used little outside of scientific research. Protactinium is found in small amounts within uranium ores, and also spent fuel rods of nuclear reactors.

Question 93

# Give the atomic number.

Answer 93

## Footnote Uranium is a silvery-gray, radioactive actinide metal. It is used in nuclear reactors, as a component in armor and ammunition, and as a colorant in glass. Uranium occurs naturally in multiple minerals like uranite (pitcheblende), carnotite, and brannerite.

Question 94

# Give the atomic number.

Answer 94

## Footnote Neptunium is a radioactive actinide metal. It is used in scientific research and as a precursor to plutonium-238. Neptunium is mostly extracted as a byproduct of nuclear reactors but also occurs naturally in trace quantities in uranium ores.

Question 95

# Give the atomic number.

Answer 95

## Footnote Plutonium is a silvery, radioactive actinide metal. It is used as a fuel in nuclear reactors, in nuclear weapons, and as a heat source in radioisotope thermoelectric generators for spacecrafts. Plutonium-239 has a half-life of 24,400 years.

Question 96

# Give the atomic number.

Answer 96

## Footnote Americium, a shiny, silvery radioactive metal, is utilized in smoke detectors, as a neutron source, and in scientific research. It's primarily produced by bombarding plutonium with neutrons in nuclear reactors, with trace amounts also found in uranium minerals and formed after nuclear weapons detonations.

Question 97

# Give the atomic number.

Answer 97

## Footnote Curium is a silvery, radioactive actinide metal used in scientific research, as a source of thermal energy in radioisotope thermoelectric generators, and as a neutron source. It is primarily produced in small amounts by bombarding plutonium with neutrons, with tiny traces also potentially found in uranium deposits.

Question 98

# Give the atomic number.

Answer 98

## Footnote Berkelium is a silvery, radioactive actinide metal. It is used in scientific research and has no practical applications outside of this due to its rarity. Berkelium is formed via neutron bombardment of plutonium-239 in nuclear reactors.

Question 99

# Give the atomic number.

Answer 99

## Footnote Californium is a radioactive actinide metal used extensively in scientific research and as a potent neutron source for industrial applications. It plays a crucial role in metal detectors for identifying water and oil layers in oil wells, locating gold and silver ores, and assessing metal fatigue and stress in airplane parts.

Question 100

# Give the atomic number.

Answer 100

## Footnote Einsteinium is a radioactive actinide metal primarily used in scientific research, lacking practical applications outside of this field. Like other transplutonium elements, it is synthesized by bombarding plutonium with neutrons in a nuclear reactor.

Question 101

# Give the atomic number.

Answer 101

## Footnote Fermium is a radioactive actinide metal primarily used in scientific research, without practical applications outside of this field. It is notable as the heaviest element that can be synthesized by neutron bombardment of lighter elements, typically plutonium, and it holds the distinction of being the heaviest element produced in macroscopic quantities (micrograms).

Question 102

# Give the atomic number.

Answer 102

## Footnote Mendelevium is a radioactive actinide metal used exclusively in scientific research, lacking practical applications beyond this domain. Its longest-lived isotope, Md-260, has a half-life of 28 days.

Question 103

# Give the atomic number.

Answer 103

## Footnote Nobelium is a radioactive actinide metal primarily used in scientific research, with no practical applications outside of this field. It has a very short half-life of only 58 minutes.

Question 104

# Give the atomic number.

Answer 104

## Footnote Lawrencium is a radioactive actinide metal utilized solely in scientific research, lacking practical applications beyond this realm. Its most stable isotope has a half-life of approximately 4 hours.

Question 105

# Give the atomic number.

Answer 105

## Footnote Rutherfordium is a synthetic transition metal that is highly radioactive and has no known uses outside of scientific research. Its isotope Rutherfordium-265 has a very short half-life of approximately 2 minutes.

Question 106

# Give the atomic number.

Answer 106

## Footnote Dubnium is a synthetic transition metal that is highly radioactive and primarily used in scientific research, with no known applications outside of this field. Its isotope Dubnium-268 has a half-life of approximately 1.2 days.

Question 107

# Give the atomic number.

Answer 107

## Footnote Seaborgium is a synthetic transition metal highly prized for scientific research, yet it holds no known applications beyond this realm. Notably, Seaborgium-271 possesses a fleeting half-life of about two minutes.

Question 108

# Give the atomic number.

Answer 108

## Footnote Bohrium is a synthetic transition metal that is highly radioactive and utilized exclusively for scientific research purposes. Its isotope Bohrium-272 has an extremely short half-life of about 10 seconds.

Question 109

# Give the atomic number.

Answer 109

## Footnote Hassium is a synthetic transition metal known for its high radioactivity and is solely utilized in scientific research, without any known applications beyond this field. The isotope Hassium-270 has a brief half-life of approximately 22 seconds.

Question 110

# Give the atomic number.

Answer 110

## Footnote Meitnerium is a synthetic transition metal that is highly radioactive and used exclusively for scientific research purposes. Its longest-lived isotope, Meitnerium-278, has a very short half-life of only 8 seconds.

Question 111

# Give the atomic number.

Answer 111

## Footnote Darmstadtium is a synthetic transition metal that is highly radioactive and is primarily employed in scientific research, lacking practical applications beyond this realm. It encompasses 15 known isotopes, with its heaviest and longest-lived isotope having a half-life of about 4 minutes.

Question 112

# Give the atomic number.

Answer 112

## Footnote Roentgenium is a synthetic transition metal known for its high radioactivity and exclusive use in scientific research. Its longest-lived isotope, Roentgenium-281, has a half-life of 22.8 seconds.

Question 113

# Give the atomic number.

Answer 113

## Footnote Copernicium is a synthetic element characterized by its lack of reactivity, resembling more a noble gas than a metal. It is highly radioactive and utilized solely in scientific research, without known applications beyond this domain. Copernicium-285, its isotope, has a half-life of approximately 29 seconds.

Question 114

# Give the atomic number.

Answer 114

## Footnote Nihonium is highly radioactive and has no known uses outside of scientific research. Additionally, Nihonium-284 has a half-life of approximately 0.48 seconds.

Question 115

# Give the atomic number.

Answer 115

## Footnote Flerovium is highly radioactive and has no known uses outside of scientific research. Flerovium-289 has a half-life of approximately 2.1 seconds.

Question 116

# Give the atomic number.

Answer 116

## Footnote Moscovium is highly radioactive and has no known uses outside of scientific research. Moscovium-288 has a half-life of approximately 0.09 seconds.

Question 117

# Give the atomic number.

Answer 117

## Footnote Livermorium is highly radioactive and has no known uses outside of scientific research. Livermorium-293 has a half-life of around 0.06 seconds.

Question 118

# Give the atomic number.

Answer 118

## Footnote Tennessine is highly radioactive and has no known uses outside of scientific research. Tennessine-294 has a half-life of about 0.08 seconds.

Question 119

# Give the atomic number.

Answer 119

## Footnote Oganesson is highly radioactive and has no known uses outside of scientific research. Oganesson-294 has a half-life of about 0.9 seconds.