Inorganic Chemistry + Periodic Table

Question 1

What happens as you go down group 2

Answer 1

• reactivity increases down the group

- ionisation energy gets lower so it is easier to be oxidised and lose an electron

Question 2

What is the general equation of group 2 metals reacting with water

Answer 2

X₍ₛ₎ + 2H₂O₍ₗ₎ –> X (OH)₂ + H₂ ₍𝓰₎

metal + water –> hydroxide + hydrogen gas

Question 3

what happens to solubility of hydroxides as you go down group 2

Answer 3

solubility increases down the group

Question 4

what does Mg(OH)₂ form (look like)

Answer 4

• white precipitate
• because it is not soluble
  (Mg is the least soluble whereas barium is the most soluble so Ba(OH)₂ will form no precipitate as it is very soluble)

Question 5

what do the hydroxides below magnesium form (look like)

Answer 5

• no precipitate
• because they are very soluble
  (solubility increases down the group)

Question 6

What is the reaction of Mg with steam

Answer 6

Mg₍ₛ₎+ H₂O₍𝓰₎ –> MgO₍ₛ₎ + H₂₍𝓰₎

Question 7

what is Magnesium oxide

Answer 7

a base so it reacts and neutralises an acid

Question 8

why does the reactivity increase down group 2?

Answer 8

• 1st and 2nd I.E decreases down the group therefore the outer electron is lost more easily
• because there is increased shielding which therefore lowers the effective charge on the nucleus
• therefore it can react easier

Question 9

what is the reaction of oxygen and a group 2 metal

Answer 9

2Mg₍ₛ₎ + O₂₍𝓰₎ –> 2MgO₍ₛ₎ (bright white flame)
2 metal + oxygen –> 2 metal oxide

• it is the same balancing with all the other group 2 metals

Question 10

what is the reaction of chlorine and a group 2 metal

Answer 10

Mg₍ₛ₎ + Cl₂₍𝓰₎ –> MgCl₂₍ₛ₎
metal + chlorine –> metal chloride

• it is all the same with all other group 2 metals

Question 11

what is the reaction of oxides with water

Answer 11

MO₍ₛ₎ + H₂O₍ₗ₎ –> M(OH)₂₍ₛ₎ (metal=m)
metal oxide + water –> metal hydroxide

• produces metal hydroxide
• magnesium is the only only hydroxide that forms a solid as it is not very soluble
• however Ca, Sr, Ba (OH)₂ are AQUEOS ₍ₐᵩ₎
  this is because they are very soluble in water (they release all (OH)₂ ions

Question 12

what is the reaction of oxides and HCL

Answer 12

MO₍ₛ₎ + 2HCL₍ₐᵩ₎ –> MCl₂₍ₐᵩ₎ + H₂O₍ₗ₎
metal oxide + HCL –> metal salt + water

e.g.- magnesium + HCL –> magnesium chloride + water

Question 13

what is the reaction of oxides and H₂SO₄

Answer 13

MO₍ₛ₎ + H₂SO₄₍ₐᵩ₎ –> MSO₄ + H₂O₍ₗ₎

metal oxide + sulfuric acid –> metal sulphate + water

Question 14

what happens to the solubility of sulphates as you go down group 2

Answer 14

• solubility decreases as you go down the group
• MgSO₄ (most soluble)
• BaSO₄ (least soluble)

Question 15

what is the reaction of hydroxides with HCL

Answer 15

M(OH)₂₍ₐᵩ₎ + 2HCL₍ₐᵩ₎ –> MCl₂₍ₐᵩ₎ + 2H₂O₍ₗ₎

they neutralise acids

Question 16

what is the reaction of hydroxides with H₂SO₄

Answer 16

M(OH)₂₍ₐᵩ₎ + H₂SO₄₍ₐᵩ₎ –> MSO₄ + 2H₂O₍ₗ₎

Question 17

are carbonates soluble or insoluble

Answer 17

insoluble

Question 18

what is thermal decomposition

Answer 18

the use of heat to break down a reactant into multiple products

Question 19

the greater the charge density (size:charge) of the ion

Answer 19

the more readily thermal decomposition occurs

Question 20

what is the only group 1 metal that can decompose

Answer 20

lithium carbonate Li₂CO₃₍ₛ₎ –> Li₂O₍ₛ₎ + CO₂₍𝓰₎

this is cuz Li has the biggest charge density
the charge density of the others elements in grp1 ions it too low so decomposition does not occur

Question 21

can all group 2 metals decompose? if yes what is the general formula

Answer 21

yes
MCO₃₍ₛ₎ –> MO₍ₛ₎ + CO₂₍𝓰₎

2⁺ charge drags one of oxygen from carbonate molecule and decomposition happens
- down the group it requires higher temps

Question 22

state the trend in thermal stability as you go down the group

Answer 22

increases

• (more stable when heated)
• more difficult to thermally decompose as charge density decreases so
• less of a polarising effect
• you will have to heat them more and more if you want them to decompose

Question 23

summary of thermal stability

Answer 23

• carbonate breaks down

- bigger charge density, more likely to pull oxygen away from the carbonate to form

Question 24

how to do a flame test

Answer 24

using nichrome wire

clean with concentrated HCL₍ₐᵩ₎

Question 25

what are the colours for 
Li
Na
K
Rb
Cs

Answer 25

Li- red
Na- yellow/orange
K- lilac
Rb- deep red
Cs- violet

Question 26

what are the colour for 
Mg
Ca
Sr
Ba

Answer 26

Mg- no colour
Ca- yellow-red
Sr- red
Ba- apple green

Question 27

Explain how flame colour arises in a flame test

Answer 27

• heat causes electrons to be promoted to higher energy levels in the atom
• electrons fall back down towards their ground state
• emitting visible light/ photons