Chapter 7: Periodicity

Question 1

What groups do s-block elements occupy?

Answer 1

1 & 2

Question 2

What groups do p-block elements occupy?

Answer 2

13 to 18

Question 3

What groups do d-block elements occupy?

Answer 3

3 to 12

Question 4

Which group did mendeleev initially omit from the periodic table?

Answer 4

Group 18 (noble gasses) as they were yet to be discovered.

Question 5

What are pnictogens?

Answer 5

Group 15 elements (N, P, As…)

Question 6

What are chalcogens?

Answer 6

Group 16 elements (O, S, Se…)

Question 7

What is the first ionisation energy?

Answer 7

The energy required to remove one electron from each atom in one mole of gaseous atoms.

Question 8

What is the equation for second ionisation energy of strontium?

Answer 8

Sr⁺ → Sr²⁺ + e⁻

Question 9

What affects ionisation energy?

Answer 9

• Atomic radius; smaller radius greater energy
• Nuclear charge; greater attraction greater energy
• Shielding: greater repulsion from electrons lower energy

Question 10

What is the trend with successive ionisation energies?

Answer 10

Increasing energy with each sucesion. Sharp increases when changing shells and subshells.

Question 11

What is the trend in first ionisation energies down a group?

Answer 11

Decreasing

Question 12

What trends occur in first ionisation energy across a period?

Answer 12

• Energy increases along S-block
• Dips into P-block for the first element before beginning to rise
• Dips again as electron pairing begins to occur but continues to rise beyond the first instance.

Question 13

What is a metal bond?

Answer 13

The electrostatic attraction of metal cations to a pool of delocalised electrons forming a giant metallic lattice. The delocalised electrons are the delocalised outer electrons of metal atoms.

Question 14

How do cations and electrons behave in a metal bond?

Answer 14

• Cations remain in a fixed position

- Electrons are delocalised and mobile

Question 15

What are the properties of metals?

Answer 15

• Conductive
• Usually a high melting point but dependant upon bond strength.
• Insoluble as any interactions would lead to a reaction

Question 16

What are giant covalent structures?

Answer 16

A series of non-metals bonded covalently in a uniform and repeatable structure.

Question 17

What are the properties of giant covalent structures?

Answer 17

• High melting and boiling point
• Insoluble due to bond strength
• Non-conductors except graphite(ene) which have delocalised electrons in their structure.

Question 18

What are the trends in boiling point across a period?

Answer 18

Increase in b.p across giant metallic structures into giant covalent structures. Then a sharp decrease with decreasing trend acoss simple molecular structures.