Inorganic Chemistry (groups 1 And 2)

Question 1

How do group 1 and 2 elements react with oxygen?

Answer 1

As you would expect, these elements react with oxygen to form oxides.
Metal + oxygen ➡️ Metal oxide
Group 1 example: 2 Na (s) + ½ O2 (g) ➡️ Na2O (s)
Group 2 example: Mg (s) + ½ O2 (g) ➡️ MgO (s)

Question 2

How do group 1 and 2 elements react with chlorine ?

Answer 2

Group 1 and 2 metals react with chlorine to form chlorides (and other halogens to form respective halides)
Metal + chlorine ➡️ Metal chloride
Group 1 example: Na (s) + ½ Cl2 (g) ➡️ NaCl (s)
Group 2 example: Mg (s) + Cl2 (g) ➡️ MgCl2 (s)

Question 3

How do group 1 and 2 elements react with acids?

Answer 3

Group 1 and 2 metals can all react with acids: bear in mind that this is dangerous if you use a very reactive one!
Metal + acid 🡪 Metal salt + hydrogen
The salt produced depends on the acid. Remember you will need to balance the charges in the formula of the salt.
Group 1 example with HCl: Na (s) + HCl (aq) 🡪 NaCl (aq) + H2 (g)
Group 2 example with HCl: Mg (s) + HCl (aq) 🡪 MgCl2 (aq) + H2 (g)
Group 1 example with H2SO4: 2 Na (s) + H2SO4 (aq) 🡪 Na2SO4 (aq) + H2 (g)
Group 2 example with H2SO4: Mg (s) + H2SO4 (aq) 🡪 MgSO4 (aq) + H2 (g)

Question 4

How do group 1 and 2 elements react with water?

Answer 4

Group 1 and 2 metals can react with water to form hydroxides and hydrogen gas.
Metal + water 🡪 metal hydroxide + hydrogen
Group 1 example: 2 Na (s) + 2 H2O (l) 🡪 2 NaOH (aq) + H2 (g)
Group 2 example: Mg (s) + 2 H2O (l) 🡪 Mg(OH)2 + H2 (g)
There is no state symbol for magnesium hydroxide on purpose, the solubility of group 2 hydroxides vary – see below.
Additionally, we will learn that magnesium reacts with steam to produce different products:
Mg (s) + H2O (g) 🡪 MgO (s) + H2 (g)

Question 5

What are the solubility trends of group 1 and 2 elements?

Answer 5

All group 1 sulfates and hydroxides are soluble.
But the group 2 sulfates and hydroxides show a trend:

HydroxiDes are more soluble DOWN the group
SulfaTes are more soluble at the TOP of the group

Question 6

What are the reaction of group 1 and two carbonates?

Answer 6

All group 2 carbonates, plus Lithium carbonate, undergo thermal decomposition (breaking down using heat).
Carbonates of other elements in group 1 do not decompose.
Metal carbonate 🡪 metal oxide + carbon dioxide
Group 1 example: Li2CO3 (s) 🡪 Li2O (s) + CO2 (g)
Group 2 example: MgCO3 (s) 🡪 MgO (s) + CO2 (g)

Question 7

What are the reaction of group 1 and two nitrates?

Answer 7

All group 1 & 2 nitrates will thermally decompose to some extent.

All group 2 nitrates, plus Lithium nitrate, undergo greater thermal decomposition.
Metal nitrate 🡪 Metal oxide + nitrogen dioxide + oxygen
2 LiNO3(s) 🡪 Li2O(s) + 2 NO2 (g) + ½ O2 (g)
Group 2 example: Mg(NO3)2 (s) 🡪 MgO (s) + 2 NO2 (g) + ½ O2 (g)

Nitrates of other elements in group 1 undergo lesser thermal decomposition.
Metal nitrate 🡪 Metal nitrite + oxygen
Group 1 example: NaNO3 (s) 🡪 NaNO2 (s) + ½ O2 (g)