Atomic Structure

Question 1

Define, in words, the term first ionisation energy

Answer 1

Energy needed to remove a mole of electrons from a mole of atoms in the gaseous state.

Question 2

Write an equation to represent the first ionisation energy for sodium.

Answer 2

Na(g) —> Na+(g) + e-

Question 3

Write an equation to represent the first ionisation energy for a Germanium atom

Answer 3

Ge(g) —> Ge+(g) +e-

Question 4

Write an equation to represent the third ionisation energy for a manganese atom

Answer 4

Mn2+(g) —> Mn3+(g) +e-

Question 5

Explain why the first ionisation energy of potassium is less than the first ionisation energy of argon.

Answer 5

Ar has less shielding than K

Ar has a stronger attraction between its nucleus and outer electrons

Question 6

Explain why the first ionisation energy of krypton is greater than the first ionisation energy of bromine

Answer 6

Kr and Br have the same shielding

Kr has more protons than Br

Question 7

Why is a Na atom bigger than a Mg atom?

Answer 7

Both atoms have he same number of electron shells
They have the same shielding
But Mg has more protons so it attracts the outer electrons more strongly

Question 8

Give the full electron configuration of a Cr3+ ion

Answer 8

1s2 2s2 2p6 3s2 3p6 3d3

Question 9

Give the full electron configuration of a Ti2+ ion

Answer 9

1s2 2s2 2p6 3s2 3p6 3d2

Question 10

Give the full electron configuration of a Cu+ ion

Answer 10

1s2 2s2 2p6 3s2 3p6 3d10

Question 11

Give the full electron configuration of an Fe2+ ion

Answer 11

1s2 2s2 2p6 3s2 3p6 3d6

Question 12

What is an orbital?

Answer 12

A region within an atom that can hold up to two electrons with opposite spins

Question 13

Explain why the first ionisation energy of sulfur is different from that of phosphorus

Answer 13

The e- removed from S is from the 3p orbital and is paired. The e- removed from P is from the 3p orbital and is not paired. Paired electrons repel

Question 14

The first ionisation energies of the elements in Period 2 change as the atomic number increases.

Explain the pattern in the first ionisation energies of the elements from lithium to neon

Answer 14

The 1st IE increases because the number of protons increases but the shielding remains the same. There is a deviation between Be and B because the 2p orbital is higher in energy than the 2s. There is a deviation between N and O because the 2p orbital is paired which causes electron pair repulsion.

Question 15

Give the full electronic configuration of Chromium (Cr)

Answer 15

1s2 2s2 2p6 3s2 3d5 4s1

Question 16

Give the full electronic configuration of Copper (Cu)

Answer 16

1s2 2s2 2p6 3s2 3p6 4s1 3d10

Question 17

Describe how electron impact ionisation works

Answer 17

The sample is vapourised and then high energy electrons are fired at it from an electron gun. An electron is knocked off each particle to form a positive ion.

Question 18

Describe how electrospray ionisation works.

Answer 18

Sample dissolved in volatile solvent
Injected through a fine hypodermic needle giving it a fine mist
Connected to the positive terminal of high voltage power supply
Sample gains a proton

Question 19

State two differences between the plum pudding model and the model of atomic structure used today
(2 marks)

Answer 19

• nucleus contains protons and neutrons

- Electrons are now arranged in energy levels/shells/orbitals

Question 20

Three key factors that will influence lonisation Energy

Answer 20

Nuclear charge
Distance from the nucleus
Shielding

Question 21

Give and explain the full electron configuration of Cu and Cr

Answer 21

• Cr:1s2 2s2 2p6 3s2 3p6 4s1 3d5
• Cu:1s2 2s2 2p6 3s2 3p6 4s1 3d10

Explanation:d block elements are more stable when they have a full,or exactly half full sub shell