Module 3

Question 1

periodicity

Answer 1

repeating physical and chemical properties

Question 2

ionisation energy

Answer 2

energy required to remove 1 electron from each of 1 mole of gaseous atoms

1st IE = X(g) –> X^+ + e^-
2nd IE = X^+ –> X^2+ + e^-

Question 3

period 2 and 3 (1st IE)

Answer 3

.generaly 1st IE increases across
.due to nucleus getting more positive
.so outer electrons are more attractive to the nucleus(decreasing atomic radius)
.electron more tightly held

.first dip
.due to the element being in a different orbital
.so outer electrons are futher from the nucleus(atomic radius increases)
.electron more losely held

.second dip
.due to outer electron being repelled by other electron in the orbital

Question 4

answering IE questions

Answer 4

.IE down group- atomic radius increases, electron sheliding increases = less attraction between outer electron and nucleus = less IE down group

.across period- atomic radius decreases, same sheilding and nuclear charge increases = more attraction between outer electron and nucleus = more IE across period

.first dip- outer electron in p orbital, so futher away from nucleus and so more shielding = less attracted to nucleus = less energy needed

second dip- outer electron repeled by the other electron in its orbital = less attraction between electron and nucleus

Question 5

sucessive ionisation energy

Answer 5

.smaller jump- electron in closer orbital so its closer to the nucleus and so its harder to remove the electron

.big jump- electron in the closer shell so its closer to the nucleus and so its harder to remove electron

Question 6

metallic bonding

Answer 6

.electrostatic attraction between cations and delocaised electrons

Question 7

metals

Answer 7

.exist as giant metallic lattices
.which conduct electricity due to the delocalised electrons
.high MP and BP due to needing alot of energy to break strong bonds

Question 8

giant covalent lattices

Answer 8

.diamond
.graphite
.graphene
.silcon
.high MP and BP due to needing alot of energy to break strong bonds
.graphite and graphene conduct electricity due to overlapping p orbitals with delocalised electrons

Question 9

Mp and Bp trends in period 2

Answer 9

.first 3 - giant metallic lattice and metallic bonds

.Si - giant covalent lattice and covalent bonds so higher

P4 - simple covalent and only induced dipole-dipole so lower than both covalent and metallic

S8- simple covalent but more electrons than P4 so stronger induced dipole-dipole

Cl2- simple covalent but less electrons than P4 so weaker induced dipole-dipole

Ar- simple covalent but less electrons than Cl2 so weaker induced dipole-dipole

Question 10

group 2

Answer 10

.all have S2 outer shell config
.make 2+ ions when oxidised

.increase reactivity due to outer electrons futher from nucleus and more sheliding

metal oxide + water -> metal hydroxide

.increasing solubility and so pH of metal hydroxide down the group

Question 11

halogens

Answer 11

.diatomic molecules
.increase in BP & MP down group due to more electrons and so stronger induced dipole-dipole

.S2P5 outer shell config
.make 1- ions when reduced

Question 12

disproportionation reactions

Answer 12

when the same substance is oxdised and reduced in a reaction

Question 13

chlorine uses

Answer 13

.water purfication
.toxic but kills bacteria

Question 14

halide ion test

Answer 14

Cl- + Ag+ -> AgCl (white precipitate) dissolves in aqueous ammonia

Br- + Ag+ -> AgBr (cream precipitate) in concentrated ammonia

I- + Ag+ -> AgI (yellow precipitate) dosent dissovle in ammoina

Question 15

carbonate ion test

Answer 15

.carbonates fizz (gives off gas)when put in acid

Question 16

sulfate test

Answer 16

.make white precipitate whe put in Ba2+

Question 17

ammonim ion test

Answer 17

.reacts with warm OH- to make NH3
.pungent smell and turns damp litmus paper blue