C7

Question 1

Explain why first ionisation energy shows general increase across period 3 (3)

Answer 1

number of protons / proton number increase OR Greater nuclear charge (1)

electrons are in same shell OR electrons experience same/similar shielding OR atomic radius decreases (1)

greater nuclear attraction on outer electrons OR electrons are attracted more strongly (to nucleus) (1)

Question 2

Define term first ionisation energy (3)

Answer 2

energy change when each atom in 1 mole

of gaseous atoms

loses an electron to form 1 mole of gaseous 1+ ions

Question 3

Explain why the first ionisation energy of B is less than Be (2)

Answer 3

In B, electron being removed is at a higher energy / vice versa

An s electron is lost in Be AND a p electron is lost in B