chapter 7

Question 1

periodicity

Answer 1

the repeating trend in properties of elements across the table

Question 2

first ionisation energy

Answer 2

the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions

Question 3

second ionisation energy

Answer 3

the energy required to remove one electron from each atom in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions

Question 4

trend in ionisation energy across a period

Answer 4

• nuclear charge increases
• same shell; similar shielding
• nuclear attraction increases
• atomic radius decreases
• first ionisation energy increases

Question 5

trend in ionisation energy down a group

Answer 5

• atomic radius increases
• more shells so shielding increases
• nuclear attraction to outer electrons decreases
• first ionisation energy decreases

Question 6

why is Boron’s 1st IE smaller than Be’s

Answer 6

• marks the filling of the 2p sub shell

- 2p sub-shell in B has a higher energy than the 2s in Be so it easier to remove

Question 7

why is O’s 1st IE smaller than N’s

Answer 7

• start of electron pairing the p-orbitals of the 2p sub-shell
• in both elements the highest energy electrons are in a 2p sub-shell
• in oxygen the paired electrons in the 2p sub-shell repel each other making it easier to remove an electron from an oxygen atom than a nitrogen atom

Question 8

metallic bonding

Answer 8

the strong electrostatic attraction between cations and delocalised electrons.

Question 9

electrical conductivity of metals

Answer 9

delocalised electrons can move through the structure carrying charge

Question 10

mp & bp (metals)

Answer 10

-most are high due to the string attraction but it varies

Question 11

solubility (metals)

Answer 11

do not dissolve

-any interactions lead to a reaction eg Na and water, not dissolving

Question 12

giant covalent, mp & bp

Answer 12

high due to strong covalent bonds

Question 13

giant covalent, solubility

Answer 13

insoluble in almost all solvents as covalent bonds are too strong

Question 14

giant covalent, electrical conductivity

Answer 14

non-conductors except graphene & graphite

- has electrons available for bonding

Question 15

periodic trend in melting points

Answer 15

• increases groups 1-4
• sharp decrease between 4-5 (transition to simple molecular)
• comparatively low from 5-8