Groups 1, 2

Question 1

name the three physical properties of group two elements

Answer 1

• ionisation energy
• atomic radius
• reactivity

Question 2

how does ionisation energy change down group two and why

Answer 2

• ionisation energy decreases down group two
• greater atomic radius, increased shielding, easier to lose an electron

Question 3

how does reactivity change down group two and why

Answer 3

• reactivity increases down group two
• increased electron shielding and atomic radius, outer (valence) electron easier to lose, reactions can occur more easily

Question 4

how does atomic radius change down group two and why

Answer 4

• atomic radius increases
• additional electron shells

Question 5

what type of reaction is a metal + water

Answer 5

redox reaction

Question 6

metal + water ->

Answer 6

metal hydroxide + hydrogen

Question 7

what kind of solution is a metal hydroxide

Answer 7

an alkaline solution

Question 8

general equation for reaction of group 2 metals with water

Answer 8

M(s) + 2H2O(l) -> M(OH)2(aq) + H2(g)

Question 9

how is a reaction with water different to one with steam

Answer 9

• steam produces a metal oxide and hydrogen
• reaction with steam is faster because it has more energy

Question 10

metal + steam ->

Answer 10

metal oxide (white powder) + hydrogen

Question 11

general equation for reaction of group 2 metal and steam

Answer 11

M(s) + H2O(g) -> MO(s) + H2

Question 12

metal + chlorine gas ->

Answer 12

metal chloride (white precipitate)

Question 13

general equation for reaction of group 2 metal + chlorine gas

Answer 13

M(s) + Cl2(g) -> MCl2(s)

Question 14

how does reactions with chlorine gas change down group two

Answer 14

• it becomes more vigorous down group 2
• because metals more reactive

Question 15

metal + oxygen ->

Answer 15

metal oxide

Question 16

general equation for group 2 metal + oxygen in normal conditions

Answer 16

2M(s) + O2(g) -> 2MO(s)

Question 17

which two group two metals dont fit the general pattern of reaction with oxygen

Answer 17

strontium and barium

Question 18

strontium/barium + oxygen ->

Answer 18

metal peroxide

Question 19

when do strontium and barium become peroxides

Answer 19

when reacting with excess oxygen and heat energy

Question 20

(with excess oxygen and heat energy)
M(s) + O2(g) ->

Answer 20

MO2

Question 21

which group 2 metals react

Answer 21

Mg-Ba

Question 22

general equation for reactions of metal oxides and water

Answer 22

MO(s) + H2O(l) -> M(OH)2(aq)

Question 23

general equation for reactions of metal oxides and dilute hydrochloric acid

Answer 23

MO(s) + 2HCl(aq) -> MCl2(aq) + H2O(l)

Question 24

general equations for metal hydroxides in water

Answer 24

—————H2O(l)——————
M(OH)2(s) ——-> M(OH)2(aq)

Question 25

general equation for reactions of metal hydroxides and dilute hydrochloric acid

Answer 25

M(OH)2(aq) + 2HCl(aq) --> MCl2(aq) + 2H2O(l)

Question 26

how does solubility of metal hydroxides change down group two

Answer 26

- solubility increases down group two - (magnesium hydroxide least soluble)

Question 27

real life uses of magnesium hydroxide

Answer 27

- antiacid (neutralises acids in the body) - neutralises acidic soil

Question 28

how does solubility of metal sulfates change down group two

Answer 28

- solubility decreases down group two - (barium sulfate least soluble)

Question 29

real life uses of barium sulfate

Answer 29

- used in medicine as 'barium metals' (allows internal organs and tissues to be imaged) - usually toxic, but cannot be absorbed into the bloodstream so safe

Question 30

how does thermal decomposition occur

Answer 30

when substances are heated in aerobic conditions

Question 31

thermal decomposition of a group 2 metal carbonate produces

Answer 31

metal oxide (white powder) + carbon dioxide

Question 32

general equation for thermal decomposition of group 2 metal carbonates

Answer 32

MCO3(s) --> MO(s) + CO2(g)

Question 33

group 2 metal nitrates undergo thermal decomposition to form

Answer 33

metal oxide + nitrogen dioxide + oxygen

Question 34

general equation for thermal decomposition of group 2 metal nitrates

Answer 34

2M(NO3)2(s) ---> 2MO(s) + 4NO2)g) + O2(g)

Question 35

what group 1 metal carbonate and nitrate acts the same as group 2

Answer 35

lithium

Question 36

thermal decomposition of group 1 metal carbonates

Answer 36

- wont decompose upon heating as they require extremely high temperatures to do so

Question 37

group 1 metal nitrates undergo thermal decomposition to produce

Answer 37

metal nitrite + oxygen

Question 38

general equation for thermal decomposition of group one metal nitrates (excluding lithium)

Answer 38

2MNO3(s) --> 2MNO2(s) + O2(g)

Question 39

describe and explain the trend in thermal stability for group 1 and 2 nitrates and carbonates

Answer 39

- become more thermal stable down the group - down group, ionic radius increases (-smaller ions at top have a higher charge density) - higher charge density - polarise more - distorts anion - weakens c-o bond /n-o bond - less thermally stable