Group 2

Question 1

What are group 2 elements sometimes called?

Answer 1

-alkaline earth metals

Question 2

Why are group 2 metals called alkaline earth metals?

Answer 2

-due to the alkaline properties of the metal hydroxides that they form

Question 3

what type of elements are group 2 elements?

Answer 3

-They are reactive metals and do not occur in the elemental form naturally
-It is the compounds that are most useful in manufacturing and industry

Question 4

why does beryllium behave differently to the rest of the group 2?

Answer 4

due to its small size

Question 5

how can group 2 hydroxides be prepared?

Answer 5

by the reaction of the metal oxide with water to form the group 2 hydroxide (e.g. SR (s) + H2O (l) —> Sr(OH)2 (aq)

Question 6

What is the solubility of group 2 hydroxides in water?

Answer 6

They are only slightly soluble in water

Question 7

what happens when a group 2 hydroxides dissolve?

Answer 7

they dissociate to release the metal cation and hydroxide OH- ions e.g. Ca(OH) (s) + aq —> Ca2+ (aq)+ 2OH- (aq)

Question 8

what happens to the solubility of the hydroxides down the group and what does this mean?

Answer 8

solubility increases, therefore the resulting solution contains more/less OH- ions and is more/less alkaline

Question 9

what pH values will these hydroxide solutions have?

Answer 9

-PH values, ranging from eight at the least soluble end to 14 at the bottom of the group

Question 10

what happens as you go down group 2 hydroxides?

Answer 10

-Solubility increases
-PH increases
-Alkalinity increases

Question 11

what is the use of Ca(OH)2?

Answer 11

agriculture because it neutralises acidic soils

Question 12

What is the use of Mg(OH)2 and CaCO3?

Answer 12

-milk of magnesia to treat indigestion as it neutralises excess system stomach acid (HCl)

Question 13

what are the uses of group 2 oxides, hydroxides, and carbonates related to?

Answer 13

their basic properties and ability to neutralise acids

Question 14

what is the use of BaSO4?

Answer 14

Diagnostic medicine

Question 15

What is the use of CaCO3?

Answer 15

construction/sculptures etc

Question 16

why do group 2 metals have reasonably high melting and boiling points?

Answer 16

Due to having strong metallic bonds in their giant metallic lattice structures

Question 17

why can group 2 metals conduct electricity in both solid and liquid (molten) phases?

Answer 17

Because the highest energy electron is found in an s-subshell

Question 18

why do reactions in group 2 elements occur?

Answer 18

Due to their ability to lose two electrons from their outer shell

Question 19

What do elements undergo when they lose electrons?

Answer 19

Oxidation

Question 20

What do group 2 atoms therefore act as?

Answer 20

Reducing agents

Question 21

as we descend group 2, what happens to the first and second ionisation energies?

Answer 21

The first and second ionisation energies decrease

Question 22

Why do the first and second ionisation energies decrease as we descend group 2?

Answer 22

-The number of shells increases/radius increases
-shielding increases
-Nuclear attraction decreases (despite an increase in nuclear charge/ number of protons)
-Easier to lose an electron less energy is needed to remove the electrons

Question 23

what would you expect to observe in the reaction between group 2 metals (e.g.barium) with water to form an alkaline hydroxide?

Answer 23

-effervescence
-Solid dissolves
-Colourless solution forms

Question 24

what would be different about the resulting solution if you were to react calcium with water rather than barium?

Answer 24

The pH of the solution would be lower as calcium hydroxide is less soluble in water than barium hydroxide so less hydroxide ions would be dissociated into the solution

Question 25

what is the reaction of magnesium with water?

Answer 25

-It is very slow- it reacts more vigourously with steam
-However the magnesium hydroxide produced decomposes to form magnesium oxide

Question 26

what are the salts of the group 2 metals?

Answer 26

White crystalline compounds

Question 27

how can the salts of group 2 metals be prepared?

Answer 27

by reacting the metal, metal oxide or metal carbonate with the appropriate acid

Question 28

If magnesium is reacted with sulphuric acid, rather than strontium, what differences would you observe as the reaction took place?

Answer 28

-solid would dissolve slower
-It would bubble less vigourously

Question 29

what is the trend in the reactivity of group 2 metals with dilute nitric acid?

Answer 29

-reactivity increases as- the electron is further away from the nucleus, atomic radius, shielding increases the number of shells increases, so nuclear attraction decreases
-This causes ionisation energy to decrease, so it’s easier to lose electrons