Trends in the periodic table

Question 1

Define the covalent radius

Answer 1

Half-the distance between two bonded atoms

Question 2

Define the 1st ionisation energy

Answer 2

Energy required to remove one mole of electrons from one mole of gaseous atoms

Question 3

Define electronegativity

Answer 3

This is a measure of the attraction an atom of an element has for bonding electrons

Question 4

What trends are displayed by the covalent radius?

Answer 4

The covalent radius increases going down the group and decreases going across the period

Question 4

Justify the trend seen in the covalent radius going down the group

Answer 4

It increases due to the increasing number of electron shells making the atom bigger

Question 5

What trends are displayed by the 1st ionisation energy?

Answer 5

The 1st ionisation energy decreases going down the group and increases going across the period

Question 5

Justify the trend seen in the covalent radius going across the period

Answer 5

It decreases due to the increasing nuclear charge pulling the electrons closer to the nucleus

Question 6

Justify the trend seen in the 1st ionisation energy going down the group

Answer 6

It decreases due to the increasing number of electron shells making the atom bigger and increased shielding as this means that the outer electrons are less strongly held

Question 6

Justify the trend seen in the 1st ionisation energy going across the period

Answer 6

It increases due to the increasing nuclear charge pulling electrons closer to the nucleus and the smaller covalent radius meaning the outer electrons are more strongly held

Question 7

What trends are displayed by electronegativity?

Answer 7

Electronegativity decreases going down the group and increases going across the period

Question 8

Justify the trend seen in electronegativity going down the group

Answer 8

It decreases due to the increasing number of electron shells making the atom bigger and the increased shielding resulting in the outer electrons being less tightly held

Question 9

Justify the trend seen in electronegativity going across the period

Answer 9

It increases due to the increasing nuclear charge pulling the electrons closer in to the nucleus and the smaller covalent radius meaning that the outer electrons are more tightly held