unit 3- periodicity

Question 1

Define first ionisation energy.

Answer 1

The energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of +1 ions.

Question 2

What three factors affect ionisation energy?

Answer 2

Atomic radius, Nuclear charge, Electron shielding.

Question 3

How does atomic radius affect ionisation energy?

Answer 3

The greater the distance between the nucleus and the outer electrons, the less the nuclear attraction. (decreases ionisation energy)

Question 4

How does nuclear charge affect ionisation energy?

Answer 4

The more protons in the nucleus of an atom, the bigger the attraction between nucleus and outer electrons (increases ionisation energy)

Question 5

How does electron shielding affect ionisation energy?

Answer 5

Inner shell electrons repel outer shell electrons, shielding effect reduces attraction between nucleus and outer electrons. (increases ionisation energy)

Question 6

Define second ionisation energy.

Answer 6

The energy required to remove one electron from each atom in one mole of gaseous +1 ions of an element to form one mole of +2 ions.

Question 7

As you go across a period, what happens to the first ionisation energy of elements?

Answer 7

Increase across each period, higher nuclear charge.

Question 8

When is there a sharp decrease in ionisation energy on the periodic table?

Answer 8

Between the end of one period and the start of the next period.

Question 9

What is the trend in ionisation energy down a group & why?

Answer 9

Decreases down the group
Atomic radius and electron shielding increase (outweighs increase in nuclear charge).

Question 10

Define metallic bonding.

Answer 10

The strong electrostatic attraction between cations and delocalised electrons to form a giant metallic lattice.

Question 11

In what state can metals conduct electricity?

Answer 11

Solid and liquid

Question 12

How do metals conduct electricity?

Answer 12

Delocalised electrons are able to carry charge

Question 13

Why do metals have high boiling points?

Answer 13

More energy needed to overcome the strong electrostatic attraction between cations and electrons

Question 14

Why do simple covalently bonded molecules have low boiling points?

Answer 14

The simple molecular lattice structure is held together by weak intermolecular forces

Question 15

What type of structure is diamond?

Answer 15

Giant covalent lattice

Question 16

What is the shape and bond angle of carbons atoms in a diamond structure?

Answer 16

109.5, tetrahedral

Question 17

Explain the boiling points of giant covalent lattices

Answer 17

High boiling point, strong covalent bonds require a lot of energy to overcome

Question 18

Explain the solubility of giant covalent lattices

Answer 18

Insoluble in all solvents, covalent bonds are too strong to be broken down

Question 19

Do giant covalent lattices conduct electricity? Why?

Answer 19

No, e.g in diamond all four outer shell electrons are involved in covalent bonding.

Question 20

Why does graphene conduct electricity?

Answer 20

Carbon only uses 3 of its 4 outer electrons, one delocalises and is able to carry charge.