Periodicty

Question 1

What is first ionisation energy ?

Answer 1

• energy required to move one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

x(g) ——–> x+(g) + e-

Question 2

Explain the trend in first IE down a group

Answer 2

= decreases
= inc atomic radius
= more e- shells
= more e- shielding
= weaker nuclear attraction on outer e -

Question 3

Explain the trend in first IE across a period

Answer 3

= increases
= nuclear charge increases
= e- are in same shell / simm sheilding
= greater nuclear attraction on outer e -

Question 4

Explain why Al has a lower first IE than Mg

Answer 4

= electron removed from 3p subshell which is at a higher energy level than 3s, so less energy required to remove e-

Question 5

Explain why Ne has a lower first IE than PBB

Answer 5

= electrons are paired in p-orbital and have repulsion so easier to remove e -

Question 6

Explain what is meant by a metallic bond?

Answer 6

= electrostatic attraction between positive ion (cation) and delocalised electrons

Question 7

what is hydrogen bonding

Answer 7

F,O,N attached to a H
H bonds are strongest IMF

Question 8

what is a non-polar molecule

Answer 8

= dipoles cancel
= symmetrical molecule