3.1.1.3 Electron Configuration

Question 1

What is first ionisation energy?

Answer 1

The energy required to remove one electron off each atom in one mole of gaseous atoms to form gaseous +1 ions
Measured in kJ mole-1

Question 2

What do large jumps between ionisation energies show?

Answer 2

It shows that there are energy shells because there is a large change in distance

Question 3

What causes ionisation energy to increase?

Answer 3

Number of protons increases
Inner shielding of electrons increases
Distance between the electron and the nucleus decreases
This is because these strengthen the electrostatic force

Question 4

Why do first ionisation energies increase across a period?

Answer 4

Electrons are added to the same energy level
Nuclear charge increases
Inner shielding and distance is similar

Question 5

Why are second ionisation energies greater than first ionisation energies?

Answer 5

The number of protons is the same
The ion is smaller
However there is less electron electron repulsion

Question 6

Why does ionisation energy decrease down a group?

Answer 6

Distance and inner shielding increases

Question 7

What are the types of sub shell?

Answer 7

S = 1 orbital, 2 electrons, circle orbit
P = 3 orbitals, 6 electrons, figure of 8 orbit
D = 5 orbitals, 10 electrons, four leaf clover orbit
F = 7 orbitals, 14 electrons

Question 8

What are the possible subshells?

Answer 8

1s
2s, 2p
3s, 3p, 3d 
4s, 4p, 4d, 4f
5s, 5p, 5d, 5f
6s, 6p, 6d
7s, 7p

Question 9

How can you draw electron orbitals?

Answer 9

Each orbit can be shown on a box with each electron represented by an arrow
In each orbital the electrons spin in opposite directions, one clockwise and one anti-clockwise
When there is more than one orbital available, each is occupied before the electrons pair up
Before pairing up individual electrons must face the right direction

Question 10

Why is Sr smaller then Rb?

Answer 10

Because there is a bigger nuclear charge and a similar level of shielding

Question 11

How do subshells relate to ionisation energy?

Answer 11

If an electron is removed from a subshells at a higher energy level, it requires more energy
E.g. Less energy is needed to remove an electron from a p subshell than an s subshell
Paired electrons are easier to remove because of electron electron repulsion

Question 12

What do atomic orbitals look like?

Answer 12

See card

Question 13

Electrons in atoms occupy orbitals. What is meant by the term orbital?

Answer 13

An orbital is a region within an atom that can hold up to two electrons with positive spins

Question 14

In an electron orbital, what do the arrows represent?

Answer 14

The spin of electrons

Question 15

What are the maximum amount of electrons in the first seven energy levels?

Answer 15

2, 8, 8, 18, 18, 32, 32

Question 16

In terms of their electronic configuration, why do magnesium and calcium have similar chemical properties?

Answer 16

Magnesium and calcium both have two s electrons in their highest occupied orbital
The electronic configuration of an element determines the chemical properties

Question 17

What is group 1 otherwise called?

Answer 17

Group s because the outer electron is in an s subshell

Question 18

What is the scale of energy for electron subshells?

Answer 18

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p

Question 19

What does isoelectronic mean?

Answer 19

When species have the same electronic configuration

Question 20

Does magnesium or aluminium have a lower ionisation energy?

Answer 20

Aluminium
This is because outer electron of Al is in the 3p subshell and the outer electron of Mg is in the 3s subshell
P orbitals are further from the nucleus so the electron is easier to remove