Periodic Table

Question 1

What is an atom?

Answer 1

The smallest part of an element that can exist.

Atoms are the basic building blocks of matter.

Question 2

Describe Dalton’s model of the atom.

Answer 2

Atoms as solid spheres that cannot be divided into smaller parts.

Dalton proposed that atoms are indivisible and maintain their identity in chemical reactions.

Question 3

What is an element?

Answer 3

A substance made of one type of atom.
E.g., oxygen = O2, iron = Fe.

Elements are pure substances that cannot be broken down into simpler substances.

Question 4

What is a molecule?

Answer 4

A particle made of two or more atoms joined together.
E.g., oxygen = O3, water = H2O.

Molecules can consist of the same or different types of atoms.

Question 5

What is a diatomic molecule?

Answer 5

A molecule that consists of two atoms, often the same.
E.g., O2, Cl2.

Diatomic molecules are important in various chemical reactions.

Question 6

What is a chemical symbol?

Answer 6

A one or two universal letter code of each element.

Chemical symbols are used to represent elements in chemical formulas.

Question 7

Where are chemical symbols of elements found?

Answer 7

In the periodic table.

The periodic table organizes elements based on their properties.

Question 8

What is a compound?

Answer 8

A substance made of more than one type of atom chemically joined together.
E.g., water = H2O, carbon dioxide = CO2.

Compounds have different properties than the elements that make them up.

Question 9

What is a chemical formula?

Answer 9

A formula that shows the number and type of atoms present in a molecule.

Chemical formulas provide essential information about the composition of compounds.

Question 10

What do the compound endings ‘ide’ and ‘ate’ mean?

Answer 10

1) ide - a compound of only the named substances.
2) ate - a compound of the named substances and oxygen.

These endings help identify the composition of chemical compounds.

Question 11

What is a physical change?

Answer 11

Changes of state as no new substances are made.

Physical changes include changes in state, shape, or size without altering the substance’s composition.

Question 12

What is a chemical change (Chemical reaction)?

Answer 12

When atoms rearrange to make new substances.

Chemical changes involve breaking and forming bonds between atoms.

Question 13

Where do we find metals in the periodic table?

Answer 13

On the left.

Metals are typically located on the left side of the periodic table and are characterized by specific physical properties.

Question 14

Where do we find non-metals on the periodic table?

Answer 14

On the right.

Non-metals are found on the right side of the periodic table and have distinct properties compared to metals.

Question 15

Who designed the modern periodic table?

Answer 15

Mendeleev.

Mendeleev organized elements based on atomic mass and properties, leading to the development of the periodic table.

Question 16

What are the groups in the periodic table?

Answer 16

Columns.

Groups contain elements with similar chemical properties.

Question 17

What are the rows called in the periodic table?

Answer 17

Periods.

Periods indicate the energy levels of the electrons in the atoms.

Question 18

What are the physical properties of most metals?

Answer 18

• Good conductors of electricity
• Good conductors of heat
• Shiny
• High density (heavy for its size)
• Malleable (can be hammered)
• Sonorous (makes a ringing sound when hit)
• Ductile (can be pulled into wires)
• High melting points (except mercury)
• Hard

Metals exhibit these characteristics due to their atomic structure.

Question 19

What are the physical properties of non-metals?

Answer 19

• Poor conductors of electricity
• Poor conductors of heat
• Dull
• Low density (light for its size)
• Brittle (breaks easily)
• Non-sonorous (no ringing sound when hit)
• Low melting points

Non-metals have distinct properties that differentiate them from metals.

Question 20

What is the formula to calculate the relative atomic mass of an element with isotopes?

Answer 20

((isotope 1 mass x abundance) + (isotope 2 mass x abundance)) ÷ 100

Question 21

How do you calculate the relative atomic mass of carbon with isotopes carbon-14 and carbon-12?

Answer 21

For carbon: ((14 × 20) + (12 × 80)) ÷ 100 = 12.4

Question 22

What do electrons occupy in an atom?

Answer 22

Electrons occupy the lowest available energy levels (the shells closest to the central nucleus).

Question 23

What does the electronic structure of an atom indicate?

Answer 23

The electronic structure tells you how many electrons are in each shell.

Question 24

What is the electronic structure of sodium?

Answer 24

2, 8, 1

Sodium has 2 electrons in shell 1, 8 in shell 2, and 1 in shell 3.

Question 25

What are atoms?

Answer 25

Atoms make up all substances and are the smallest part of an element that can exist

Question 26

What do chemical symbols represent?

Answer 26

Chemical symbols represent an atom of an element; e.g., Na represents an atom of sodium

Question 27

How are compounds formed?

Answer 27

Compounds are formed from elements by chemical reactions

Question 28

What do compounds contain?

Answer 28

Compounds contain two or more elements chemically combined in fixed proportions

Question 29

Give an example of a compound and its composition.

Answer 29

HCl is a compound containing 1 atom of hydrogen and 1 of chlorine per molecule

Question 30

How can compounds be separated into elements?

Answer 30

Compounds can only be separated into elements by chemical reactions

Question 31

What is a mixture?

Answer 31

A mixture consists of two or more elements or compounds not chemically combined together

Question 32

What happens to the chemical properties of substances in a mixture?

Answer 32

The chemical properties of each substance in the mixture are unchanged

Question 33

How can mixtures be separated?

Answer 33

Mixtures can be separated by: * filtration * crystallisation * simple distillation * fractional distillation * chromatography

Question 34

What distinguishes the separation of mixtures from compounds?

Answer 34

Separation of mixtures involves physical processes, so no new substances are made

Question 35

What was the first model of the atom?

Answer 35

Atoms were thought to be tiny spheres that could not be divided

Question 36

What is the plum pudding model?

Answer 36

The plum pudding model describes the atom as a ball of positive charge with negative electrons embedded in it

Question 37

What conclusion was drawn from the alpha particle scattering experiment?

Answer 37

The mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged

Question 38

Describe the alpha particle scattering experiment.

Answer 38

A beam of alpha particles was aimed at very thin gold foil; some particles were deflected at different angles and some came straight back

Question 39

What did the scattering experiment reveal about the nucleus?

Answer 39

Positively charged alpha particles were being repelled and deflected by a small concentration of positive charge in the atom (nucleus)

Question 40

What did Neil Bohr suggest about electrons?

Answer 40

Neil Bohr suggested that electrons orbit the nucleus at specific distances

Question 41

True or False: A mixture can only be separated by chemical reactions.

Answer 41

False

Question 42

Fill in the blank: Compounds can only be separated into elements by _______.

Answer 42

chemical reactions

Question 43

What is the positive charge of any nucleus subdivided into?

Answer 43

Whole number of smaller particles called protons

Question 44

Who provided the evidence for the existence of neutrons?

Answer 44

James Chadwick

Question 45

What is the atomic number?

Answer 45

The number of protons in an atom of an element

Question 46

Do all atoms of a particular element have the same number of protons?

Answer 46

Yes

Question 47

What is the relative charge of a proton?

Answer 47

+1

Question 48

What is the relative charge of a neutron?

Answer 48

0

Question 49

What is the relative charge of an electron?

Answer 49

-1

Question 50

What must be true for an atom to have an overall charge of 0?

Answer 50

Number of protons = number of electrons

Question 51

What is the approximate radius of an atom?

Answer 51

About 0.1 nm

Question 52

How does the radius of a nucleus compare to that of an atom?

Answer 52

Less than 1/10,000 of that of the atom

Question 53

What is the mass number?

Answer 53

The sum of the protons and neutrons in an atom

Question 54

What are isotopes?

Answer 54

Atoms of the same element with different numbers of neutrons

Question 55

What does the mass number indicate in the periodic table?

Answer 55

Total number of protons and neutrons

Question 56

If an atom has a mass number of 19 and 9 protons, how many neutrons does it have?

Answer 56

10 neutrons

Question 57

What is relative atomic mass?

Answer 57

An average value that takes account of the abundance of the isotopes of the element

Question 58

What does the atomic number indicate?

Answer 58

The number of protons in an atom

Question 59

Fill in the blank: Atoms are very small, with a radius of about _______.

Answer 59

0.1 nm

Question 60

True or False: An electron has a relative mass of 1.

Answer 60

False

Question 61

What is the relative mass of a proton?

Answer 61

1

Question 62

What is the relative mass of a neutron?

Answer 62

1

Question 63

What is the relative mass of an electron?

Answer 63

Very small