GCSE follow-through concepts

Question 1

Relative isotopic mass

Answer 1

The mass of the isotope relative to 1/12 of the mass of a carbon-12 atom

Question 2

The mass of which atom are the masses of other atoms measured relative to?

Answer 2

Carbon-12

Question 3

Relative isotomic mass (Ar)

Answer 3

The weighted average of the masses of the isotopes on a scale where the mass of a carbon-12 atom is exactly 12 units

Question 4

Relative formula mass (Mr)

Answer 4

The weighted average of the masses of the formula units on a scale on which the mass of a carbon-12 atom is exactly 12 units

Question 5

Molecular formula

Answer 5

Elements in a molecule and the number of atoms of each element

Question 6

Empirical formula

Answer 6

Simplest whole number ratio of the atoms of each element in a compound

Question 7

How do you calculate Mr?

Answer 7

add up each individually multiplied molecule in the compound

Question 8

How do you calculate the percentage of an element in a compound?

Answer 8

Ar of that element
————————— x100
Total Mr

Question 9

How do you calculate the mass of an element produced/required for a reaction?

Answer 9

Mr?
—— x mass
Mr √

Question 10

How do you form empirical formulas?

Answer 10

% or mass
————– (then use a ratio)
Ar

Question 11

What is the Avogadro constant?

Answer 11

The number of atoms per mole of the carbon-12 isotope

Question 12

What’s a mole?

Answer 12

The amount of any substance containing as many particles as there are carbon atoms in 12g of the carbon-12 isotope.

Question 13

What’s the mass, moles and Mr triangle?

Answer 13

Mass
—————
Moles | Mr

Question 14

How do you work out the % of a product?

Answer 14

Mass produced
———————- x 100
Maximum possible

Question 15

What are isotopes?

Answer 15

Isotopes are atoms of the same element with the same number of protons, yet a different number of neutrons, therefore the atomic number remains the same, whilst the mass number changes.

Question 16

What does the nucleus of an atom contain and what are their charges?

Answer 16

Positively charged protons and neutral neutrons

Question 17

What’s in the shell of an atom and what are their charges?

Answer 17

Negatively charged electrons

Question 18

What are the masses of protons, neutrons and electrons?

Answer 18

Protons and neutrons = 1 unit
Electrons = 0 units (incredibly light)

Question 19

How are atoms charged and why?

Answer 19

They have no charge as there’s an equal number of protons and electrons

Question 20

What does the atomic/proton number show us?

Answer 20

The number of protons in an atom

Question 21

What does the nucleon/mass number show us?

Answer 21

The number of protons and neutrons in an atom

Question 22

How do we work out the number of neutrons in an atom?

Answer 22

Mass number - atomic number

Question 23

In which direction are groups on the periodic table and what do they show us?

Answer 23

Downwards, showing us the amount of outer electrons an atom has

Question 24

In which direction are periods on the periodic table and what do they show us?

Answer 24

Across, showing us the amount of orbits an atom has

Question 25

When are ions formed?

Answer 25

When a non-metal and a metal come into close contact

Question 26

Do metals or non-metals have a pretty full outer orbit?

Answer 26

Non-metals

Question 27

Do ions have a charge? Why?

Answer 27

Yes, as they contain a different number of protons and electrons

Question 28

How are covalent bonds formed and with what type of atoms?

Answer 28

Between non-metals, who have to lose or gain three or four electrons, therefore they bond to share pairs of electrons through a covalent bond

Question 29

Which number do you look at on the periodic table for bonding questions?

Answer 29

The top one

Question 30

What do elements with a covalent bond create?

Answer 30

A molecule

Question 31

How are molecules charged?

Answer 31

They have no charge or loose electrons

Question 32

What is molar mass measured in?

Answer 32

gmol-1

Question 33

What are the different symbols commonly used for mass, moles and Mr?

Answer 33

Mr - M
Mass - m
Moles - n

Question 34

Do you use the big numbers to calculate relative formula mass?

Answer 34

Never