The periodic table

Question 1

where are metals and non metals on the periodic table

Answer 1

metals, left
non metals, right

Question 2

define first ionisation energy

Answer 2

energy needed to remove 1 electron from each atom in 1 mole of a gaseous atom to form 1 mole of gaseous 1+ ions

Question 3

describe the trends in first ionisation energy

Answer 3

• decreases down a group due to increased atomic radius and shielding, so lower nuclear attraction
• increases across a period due to increased nuclear charge and decreasing atomic radius despite electron shielding staying the same

Question 4

explain the 2 drops in ionisation energy across a period

Answer 4

2-3 ) electrons removed from p orbitals are easier to remove than ones from s because of increased shielding and atomic radius
5-6 ) in group 6, electrons are paired unlike in group 5 so they repel more and are easier to lose

Question 5

what are the 2 main rules about successive ionisation energies

Answer 5

• they increase within the same shell
• there’s large jumps between shells

Question 6

what is metallic bonding and its properties

Answer 6

strong electrostatic attraction between positive ions and delocalised electrons
-high melting and boiling points
-malleable
-good electrical conductors
-ductile
-form giant metallic lattice structures

Question 7

how is the periodic table arranged and explain periods and groups

Answer 7

• by increasing atomic number
• periods show repeating trends in physical and chemical properties
• groups have similar chemical properties

Question 8

describe diamond, graphite and graphene

Answer 8

diamond - a carbon bonded to 4 others
- excellent heat conductor
- doesn’t conduct electricity
- hard
- insoluble in water
- tetrahedral structure
graphite - a carbon bonded to 3 others in a hexagonal pattern
- conducts heat and electricity
- delocalised electron
- layers slide over ( lubricant )
- insoluble in water
- weak electrostatic attraction between sheets
graphene - one sheet of graphite

Question 9

describe silicon

Answer 9

• solid giant covalent lattice
• atoms arranged in tetrahedral structure
• semi conductors of electricity
• insoluble in water
• high melting and boiling points

Question 10

describe structure, forces and bonding across period 3

Answer 10

Na,Mg,Al) giant metallic
-strong attraction between cations and electrons
-metallic bonding
Si) giant covalent
-strong forces between atoms
-covalent bonding
P4,S8,Cl2,Ar) simple molecular
-weak intermolecular forces
-covalent bonding within molecules

Question 11

describe structure, forces and bonding across period 2

Answer 11

Li + Be) giant metallic
-strong attraction between cations and electrons
-metallic bonding
B + C) giant covalent
-strong electrostatic forces between atoms
-covalent bonding
N2,O2,F2,Ne) simple molecular
-weak intermolecular forces
-covalent bonding within molecules

Question 12

how do Group 2 elements form ions

Answer 12

the outer shell s2 electron is lost in redox reactions to form 2+ ions

Question 13

Reaction of Group 2 with oxygen

Answer 13

2M(s) + O2(g) = 2MO (s)

Question 14

Reaction of Group 2 with water

Answer 14

M(s) + 2H2O(l) = M(OH)2 + H2(g)
-gets more vigorous as you go down the group

Question 15

Reaction of Group 2 with dilute acids

Answer 15

metal + acid = salt + hydrogen
M(s) + 2HCl(aq) = MCl2(aq) + H2(g)

Question 16

what happens to reactivity as you go down Group 2 and why

Answer 16

increases as ionisation energy decreases bc more electron shielding, higher atomic radius and so less energy needed to lose the electrons

Question 17

Reaction of Group 2 oxides with water

Answer 17

MO(s) + H20(l) = M2+(aq) + 2OH-(aq)

Question 18

what happens to the solubility of hydroxides as you go down Group 2

Answer 18

increases
more OH- ions
more alkaline

Question 19

what are the real life uses of:
Ca(OH)2
Mg(OH)2 and CaCO3

Answer 19

Ca(OH)2 - agriculture to neutralise acid soils
Mg(OH)2 and CaCO3 - antacids in treating indigestion

Question 20

how do Group 7 elements form ions
and describe halogens

Answer 20

Halogens are diatomic molecules and are oxidising agents
-outer shell s2p5 gains 1 electron to form 1- ions

Question 21

what is the boiling point trend as you go down group 7

Answer 21

increases because the molecule gets larger and so induced dipole-dipole interactions (London Forces) get stronger and harder to break

Question 22

what is the trend in reactivity as you go down Group 7 and how is this tested

Answer 22

reactivity decreases
seen in displacement reactions between the halides

Question 23

what is a disproportionation reaction and give 2 examples

Answer 23

• when a species is reduced and oxidised at the same time
  -eg reaction of chlorine with water as used in water purification
  -eg reaction of chlorine with cold, dilute aqueous sodium hydroxide, as used to form bleach

Question 24

assess the benefits and risks chlorine use in water treatment

Answer 24

benefit - kills bacteria
risk - hazards of toxic chlorine gas and possible risks from formation of chlorinated hydrocarbons that can be carcinogenic

Question 25

describe the appearance and state of group 2 halogens at room temperature

Answer 25

F2 - pale yellow gas Cl2 - pale green gas Br2 - red/brown liquid I2 - shiny grey-black solid

Question 26

describe the strength of the oxidising agent ability of halogens as you go down the group

Answer 26

weakens

Question 27

describe the test for carbonates

Answer 27

add dilute HCl, and co2 gas should be produced -to test, bubble gas through limewater and it will turn cloudy

Question 28

describe the test for sulphates

Answer 28

add dilute HCl and then dilute BaSO4, a white precipitate of the barium sulphate should form

Question 29

describe the test for halogens

Answer 29

- add dilute nitric acid and then dilute silver nitrate -Cl should make white precipitate -Br should make cream precipitate -I should make yellow precipitate - to confirm, react w dilute and concentrated ammonia. Cl will dissolve in both Br will only dissolve in concentrated I won't dissolve in either

Question 30

describe the test for ammonia

Answer 30

- heat gently with warm sodium hydroxide to form ammonia gas -test gas produced with damp red litmus paper, should turn blue

Question 31

equation for the test for halides and sulphates

Answer 31

Ag+ + X- = AgX(s) Ba2+ + SO42- = BaSO4(s)