Section 1 - Periodicity

Question 1

What is the trend in atomic radius across a period and why?

Answer 1

Decreases

• number of protons increases
• electrons are more attracted to nucleus

Question 2

What is the trend in ionisation energy across a period and why?

Answer 2

Increases

• Number of protons increases
• Electrons are more attracted to the nucleus

Question 3

What are the period 3 mpts?

(graph)

Answer 3

Question 4

What is the structure and bonding of Na, Mg and Al?

Answer 4

Metals with metallic bonding - metal ions in a sea of delocalised electrons.

Question 5

What is the trend in mpts of Na, Mg and Al and why?

Answer 5

Increases - metallic bonds get stronger because…

• metal ions have increasing positive charge
• increasing no. of electrons
• decreasing radius

Question 6

What is the structure and bonding of Si?

Answer 6

Macromoleular with a tetrahedral structure - bonded with strong covalent bonds.

Question 7

What is the mpt of Si like and why?

Answer 7

Very high - a lot of energy is required to overcome strong covalent bonds.

Question 8

What is the structure and bonding of P, S and Cl?

Answer 8

Molecular - held together by Van der Waals.

Question 9

What is the formula for a P molecule?

Answer 9

P₄

Question 10

What is the formula of a S molecule?

Answer 10

S₈

Question 11

What is the formula of a chlorine molecule?

Answer 11

Cl₂

Question 12

What are the mpts of P, S and Cl like and why?

Answer 12

Low because…

• Van der Waals are weak to overcome.

Question 13

Which of P, S and Cl has the highest mpt and why?

Answer 13

S - it is the biggest molecule (S₈)

Question 14

What is the structure and bonding of Ar?

Answer 14

Ar exists as individual atoms held together by VdWs.

Question 15

What is the mpt of Ar like?

Answer 15

Very low - hardly any VdWs.