Periodicity

Question 1

How is an element defined as s,p,d, or f block?

Answer 1

According to its position on the periodic table

Question 2

State and explain the trend in atomic radius across a period

Answer 2

1. Decreases
2. Nuclear charge increases while shielding remains similar

Question 3

State and explain the general trend in first ionisation energies across a period

Answer 3

1. Decreases
2. Nuclear charge increases, electrons are more strongly attracted to the nucleus

Question 4

Describe and explain the trend in melting point across a period

Answer 4

Increases for the first 3 elements as metallic bond strength increases. Highest melting point at element 4 due to giant covalent structure with many strong bonds. Mpt then decreases due to weak VDW forces between molecules and atoms

Question 5

State the two elements that deviate from the trend in ionisation energy across a period and explain why

Answer 5

The third element due to have an outer electron in the p orbital which is higher in energy therefore easier to remove.
The sixth element due to the pairing of electrons in a p orbital which repel making it easier to remove an electron

Question 6

How can successive ionisation energies help identify an element?

Answer 6

Look for a large increase in the data to find the number of electrons in the outer main energy level