AS.2 Atomic Structure

Question 1

Atomic number

Answer 1

Number of protons

Question 2

Mass number

Answer 2

Number of protons and neutrons

Question 3

Isotope

Answer 3

Atoms of the same element with a different number of neutrons but the same number of protons in the nucleus

Question 4

Relative molecular mass

Answer 4

Weighted mean mass of one molecule compared to 1/12th of the mass of an atom of carbon-12

Question 5

Relative formula mass

Answer 5

Weighted mean mass of one formula unit compared to 1/12th of the mass of a carbon-12 atom

Question 6

Electron configuration

Answer 6

2, 8, 18, 32

Question 7

Sub shells

Answer 7

s2, p6, d10, f14

Question 8

Orbitals

Answer 8

Holds 2e-

Question 9

Energy level diagrams

Answer 9

Don’t pair e- until you have to

Fill 4s before 3d

Remove from 4s before 3d

Question 10

Shell pattern

Answer 10

1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2

Question 11

Orbital shapes

Answer 11

S - sphere

P - dumbbell

Question 12

Ions

Answer 12

Charged atoms

Question 13

Ionisation energy

Answer 13

Minimum amount of energy required to remove one mole of electrons from one mole of gaseous atoms

Question 14

Ionisation equation

Answer 14

X+ (g) —————> X2+ (g) + e-

Always positive!!

Question 15

First ionisation energy trend down a group

Answer 15

Atomic radius increase

Shielding increase

Nuclear attraction decrease

First ionisation energy decrease

Question 16

First ionisation energy trend across a period

Answer 16

Atomic radius decrease

Shielding stays constant

Nuclear charge increase

Nuclear attraction increase

First ionisation energy increase

Question 17

Anomalies in first ionisation energy in group 2-3

Answer 17

Group 3 lower than group 2

P sub shell of group 3 is higher in energy than s sub shell of group 2

P electron of group 3 is less attracted to the nucleus

Therefore p electron of group 3 requires less energy to be removed

Question 18

Anomalies in first ionisation energy in group 5-6

Answer 18

First ionisation of group 6 is less than 5

Both valence electrons are in p sub shell

In group 6, paired electron in one of the p orbitals repel each other

Less energy required to be removed

Question 19

Successive ionisations

Answer 19

General increase - less electrons are attracted by same number of protons so nucleus attraction increases and more energy required to remove

Big jumps when being removed from a new shell - a lot closer to nucleus and so more attracted