Atoms

Question 1

What does half-life mean?

Answer 1

The half-life of a radioisotope is the amount of time it takes a radioactive isotope to decay to half its original value.

Question 2

What does radioactive decay mean?

Answer 2

the process where an unstable atom loses energy through radiation. These can be emitted through alpha, beta and gamma rays.

Question 3

Sub-atomic Particles

Answer 3

neutrons, protons and electrons

Question 4

Name the charge of sub-atomic particles

Answer 4

Neutrons - neutral
Protons - positive
Electrons - negative

Question 5

What is a nucleus

Answer 5

A nucleus is the centre of an atom and contains protons and neutrons. These particles are held together through very strong forces.

Question 6

What is an isotope?

Answer 6

An isotope is an atom of the same element that differs in the number of neutrons, hence affecting its total mass.

Question 7

What is the atomic number?

Answer 7

The atomic number is found on the bottom left-hand side of the element symbol and indicates its number of protons and electrons.

Question 8

What is the mass number?

Answer 8

The mass number is the sum of the protons and neutrons in the nucleus and is indicated on the top left-hand side of the elemental symbol

Question 9

What are protons?

Answer 9

Protons are positively charged particles found in the nucleus of an atom

Question 10

What are neutrons?

Answer 10

neutrons are particles with no electrical charge that are found in the nucleus of an atom

Question 11

What are electrons?

Answer 11

Electrons are negatively charged particles that orbit the nucleus in shells. The further shell they are in = the more energy they have. Electrons are very light and move aorund very quickly.

Question 12

What are valence electrons?

Answer 12

Valence electrons are electrons found in the outermost shell. These valence electrons contain the most energy

Question 13

Draw and label a diagram of an atom

Question 14

List the number of protons, electrons and neutrons using the lithium atom. This atom has an atomic mass of 6.941 and a atomic number of 3.

Answer 14

Lithium has 3 protons, 3 electrons and 3.941 neutrons.

Question 15

What process do particle equations represent?

Answer 15

Radioactive decay

Question 16

During radioactive decay mass or charge can…..

Answer 16

neither be created nor destroyed

Question 17

What must the total mass of particles equal after nuclear decay?

Answer 17

The sum of the masses of the particles before the nuclear decay

Question 18

What type of decay has occurred if the mass is the same but the atomic number increases?

Answer 18

Beta decay has occurred and an electron has been added.

Question 19

what are alpha particles?

Answer 19

positively charged helium atoms, consisting of 2 protons and 2 neutrons, cannot travel easily through materials and can be stopped by a sheet of paper or human skin. pose little damage to humans but can cause damage through inhalation, injection or digestion

Question 20

If helium has been added to another atom what type of decay has occured?

Answer 20

alpha radiation

Question 21

What are beta particles?

Answer 21

can have a positive or negative charge and travel at high speeds. can penetrate human skin but not plastic wood or aluminium

Question 22

What is the symbol for alpha, beta and gamma?

Answer 22

α, β, γ

Question 23

What are gamma rays?

Answer 23

Gamma rays are not particles but bursts of energy released after alpha or beta particles are emitted. Can cause serious damage and can be stopped through a thick layer of concrete

Question 24

How many days will it take for tritium to fall to a quarter of its origianl mass. The half life of 100g of tritium is 4500 days.

Answer 24

So, it takes 4500 days to reach 50 grams. Which is half, so if we half again to reach a quarter (25g) we get 9000 days to reach a quarter of its original mass.

Question 25

Why is radiation helpful/useful?

Answer 25

Radiotherapy uses radioisotopes or X-rays to kill cancer cells or prevent them from multiplying. Radioactive substances can also be inserted into the body to detect the cause of disease. Body scans can also be performed through the manipulation of gamma rays to obtain images of the parts of the body inside. Gamma rays can also be exposed to foods to help prevent them from spoliing.

Question 26

External radiotherapy, internal radiotherapy/brachytherapy

Answer 26

External radiotherapy - cancer treatment where radiation is directly applied from an external machine to the site of cancer Internal Radiotherapy/Brachytherapy - Radioisotopes are placed inside the body, near, or at the cancer

Question 27

What are the dark side of radioactivity?

Answer 27

High levels of energy from nuclear reactors can cause serious, injury, disease or death and can pose a significant risk to your health. Nuclear weapons, when detonated, release enormous amounts of heat and radiation which spread out from the centre of the blast known as ground zero. This emmision of heat and radiation is known as thermal flash. Any mass amounts of energy can contaminate produce, soil, milk and will eventually result in human ingestion.

Question 28

What is nuclear fallout?

Answer 28

Nuclear fallout is when the residue and irritated particles begin to come back dowwn to Earth, a few weeks after a nuclear explosion.

Question 29

Postive Ion

Answer 29

when there are more protons in the nucleus

Question 30

Negative Ion

Answer 30

when there are more electrons than protons

Question 31

Neutral atom

Answer 31

all protons and electrons are equal and the neutrons summed with protons is equal to the mass number

Question 32

What type of radiation is least ionising?

Answer 32

Gamma radiation because it won't easily strip electrons from other atoms.

Question 33

What determines the motion of particles in matter?

Answer 33

Energy

Question 34

Where do controlled fission reactions occur

Answer 34

Nuclear Power Plants

Question 35

What happens in beta radiation?

Answer 35

In this particular radiation, one of the neutrons in the nucleus splits up into a proton and anelectron. The proton stays with the atom changing the atomic number. The electron is emitted from the nucleus, and becomes the emitted beta particle.

Question 36

What term describes a atom joined wityh 2 or more other atoms?

Answer 36

Molecule

Question 38

What are changes in state?

Answer 38

Physical changes that do not change the chemical composition.

Question 39

What is matter composed of?

Answer 39

particles

Question 40

What radiation is good for sterilising equipment?

Answer 40

Beta radiation is good for hygiene as it kills bacteria

Question 41

What does Bohr's model present?

Answer 41

that electrons orbit in energy levels.

Question 42

How are elements arranged by?

Answer 42

Increasing atomic number

Question 43

Instrument used to detect radioactcivity

Answer 43

geiger counter

Question 44

When does radioactive decay occur?

Answer 44

when the nucleus of an atom is unstable

Question 45

How is relative molecular mass calculated

Answer 45

through adding the relative atomic masses of each atom in the molecule

Question 46

Electric charge of a alpha particle

Answer 46

+2