11 - group 2

Question 1

alkaline earth metals

Answer 1

elements in group two of the periodic table

Question 2

Be configuration

Answer 2

1s²
2s²

Question 3

Mg configuration

Answer 3

1s²
2s² 2p6
3s²

Question 4

Ca configuration

Answer 4

1s²
2s² 2p6
3s² 3p6
4s²

Question 5

Sr configuration

Answer 5

1s²
2s² 2p6
3s² 3p6 3d10
4s² 4p6
5s²

Question 6

Ba configuration

Answer 6

1s²
2s² 2p6
3s² 3p6 3d10
4s² 4p6 4d10
5s² 5p6
6s²

Question 7

metallic radius of an atom

Answer 7

half the distance between the nuclei in a giant metallic lattice

Question 8

Be, Mg, Ca, Sr, Ba —–>

Answer 8

. metallic radius increases (each two outer electron occupy a shell further away)
. atomic radius increases
. melting and boiling point decrease
. density increases (Mg lower than Ca)
. decreasing IE (Mg —> Mg2+ + 2e¯)
.reactivity increases (more shielding, more distance between outer electrons and nucleus > nucleus charge)
. solubility decreases

Question 9

sulfuric acid + Ca/Sr/Ba

Answer 9

. insoluble layer formed on metal surfaces
. reactions stopped

Question 10

group 2 reactions with oxygen

Answer 10

. burn rapidly
. form white solid oxides
. oxide (eg MgO) is basic in character
. reactivity increases down
. Ba so reactive it is stored under oil

Question 11

calcium flame test

Answer 11

brick red colour

Question 12

strontium flame test

Answer 12

scarlet red colour

Question 13

barium flame test

Answer 13

apple green colour

Question 14

basic oxide + dilute acid —->

Answer 14

salt + water

Question 15

which group two oxides are neutralised by dilute HCl

Answer 15

MgO, CaO, SrO, BaO

Question 16

group 2 oxide + sulfuric acid

Answer 16

. group two has decresing solublilty
. insoluble sulfates form at surface of oxide preventing reaction
. more reaction occure when ocide is in power form

Question 17

Mg reaction with water

Answer 17

. cold water = slow reaction
Mg + 2H20 —> Mg(OH)2 + H2

. hot Mg + steam = vigorous reaction
Mg + H20 —> MgO + H2

Question 18

calcium reaction with water

Answer 18

Ca + 2H2O —> Ca(OH)2 + H2
. steady stream of hydrogen gas
. forms cloudy white suspension of soluble calcium hydroxide
. cacium oxide that dissolves forms limewater solution

Question 19

saturated solution

Answer 19

a solution which can dissolve no more aolute at a particular temperature

Question 20

group 2 oxides + water

Answer 20

makes metal hydroxide
MgO + H2O —> Mg(OH)2

. calcium oxide and water is very vigorous reaction
CaO + H2O —> Ca(OH)2

when excess water, some CaOH dissolves
Ca(OH)2 —> Ca2+ + 2OH¯

OVERALL DESCRIPTION
O²¯ + H2O —> 2OH¯

Question 21

group 2 oxide + water

Answer 21

down the group = alkalinity increases

Question 22

group 2 hydroxide solublity

Answer 22

down the group = solublilty increases

Question 23

group 2 hydroxides + dilute acids

Answer 23

hydroxide + dilute acid —> salt + water

. barium sulfate = white precipitate
. barium chloride = colourless solution

Question 24

group 2 carbonates reaction

Answer 24

. general formula = XCO3
. Mg, Ca, Sr, Ba CO3 ALL WATER INSOLUBLE
. these carbonates react with dilute acids:
metal carbonate + dilute acid —> salt + water + carbon dioxide

. MgSO4 is water soluble
. Ca, Sr, Ba - insoluble sulfate layer, stops further reaction

. Mg, Ca, Sr, Ba carbonates + HCl = soluble chloride salts

Question 25

thermal decomposition

Answer 25

the breakdown of a compou d by heat into two or more different substances

Question 26

thermal decomposition of group 2 carbonate

Answer 26

MgCO3 ----heat---> MgO+ CO2 temperature increases down group 2

Question 27

temperature for thermal decomposition of group 2 carbonate

Answer 27

down the group = temperature increases

Question 28

thermal decomposition of group 2 nitrate

Answer 28

2Ca(NO3)2 ---heat---> 2CaO + 4NO2 + O2 4NO2 is brown toxic gas, nitrogen IV oxide

Question 29

temperature for thermal decomposition of group 2 nitrate

Answer 29

down the group = temperature increases

Question 30

temperature for thermal decomposition of group 2 nitrate

Answer 30

down the group = temperature increases