PMT Group 1 and 2 Flashcards
What is a common name
given to group 2 metals?
Alkaline earth metals
What is the most reactive
metal of group 2?
Barium
List 3 physical properties of
group 2 metals
● High melting and boiling points
● Low density metals
● Form colourless (white) compounds
The highest energy electrons
of group 2 metals are in which
subshell?
S subshell
Does reactivity increase or
decrease down group 2?
Why?
● Increases
● Electrons are lost more easily because larger
atomic radius and more shielding.
What happens to the first
ionisation energy as you go
down group 2? Why?
Decreases because:
-Number of filled electron shells increases down the group →
increased shielding
- Increased atomic radius → weaker force between outer - -
-Electron and nucleus → less energy needed to remove
electron
What type of reaction is the
reaction between group 2
elements and oxygen?
Redox reaction
Write an equation for the
reaction of calcium and
oxygen
2Ca (s) + O2 (g) → 2CaO (s)
What are the products when
group 2 elements react with
water?
Hydroxide and hydrogen gas
Which group 2 element
doesn’t react with water?
Beryllium
Which group 2 element reacts
very slowly with water?
Magnesium
What type of reaction is the
reaction between group 2
metal and water?
Redox reaction
Write an equation for the
reaction of barium and
water
Ba (s) + 2H2O (l) → Ba(OH)₂ (aq) + H₂ (g)
What is oxidised and what is
reduced in a reaction between
group 2 metal and water?
Metal → oxidised
One hydrogen atom from each water →
reduced
What are the products when a
group 2 oxide reacts with an
dilute acid?
Salt and water
Write an equation for the
reaction of calcium oxide
and hydrochloric acid
CaO (s) + 2HCl (aq) → CaCl2
(s) + H₂O
(l)
What is formed when group 2
oxides react with water?
Metal hydroxide
Write an equation for the
reaction between a group 2
oxide and water
MO (s) + H2O (l) → M(OH)2
(aq)
What group 2 metal oxide is
insoluble in water?
Beryllium oxide
Write an equation for the
reaction between Mg(OH)2
and nitric acid
2HNO3 (aq) + Mg(OH)2 (aq) Mg(NO3)2(aq) + 2H2O (l)
What is the trend in hydroxide
solubility down group 2?
Increases down the group
Mg(OH)₂ is slightly soluble
Ba(OH)₂ creates a strong alkaline solution
What is the trend in sulphate
solubility down group 2?
Group 2 sulphates become less soluble
down the group with BaSO4 being the
least soluble.
Explain the reasons for the
trend of thermal stability in
group 1 and 2 carbonates
Group 2 carbonates are more thermally stable as you go down the group this is because the cations get bigger so therefore have less of a polarising effect distorting the carbonate ion less. As C-O bond is not weakened as much it harder to break down
Group 1 carbonates do not decompose except for lithium. This is because they don’t have a big enough charge density to polarise the carbonate ion as they only form 1+ ions. However Lithium ion is small enough to have a polarising effect so therefore lithium carbonate can decompose.
Explain the reasons for the
trend of thermal stability in
group 1 and 2 nitrates
The ease of thermal decomposition decreases down group 2 and this is because down the group the ions get larger and therefore has less charge density = less polarisation of nitrate anion and less weakening of the N―O bond. Group 1 nitrate do not decompose with the exception of Lithium nitrate. Lithium ion is smaller enough to charge polarisation of the nitrate anion and thus weakening the N-O bond.
Fill in the flame colours for these group 1 and group 2 elements: Lithium Sodium Potassium Rubidium Caesium Magnesium Calcium Strontium Barium
Lithium : Scarlet red Sodium : Yellow Potassium : lilac Rubidium : red Caesium: blue Magnesium: no flame colour (the energy emitted is outside visible spectrum) Calcium: brick red Strontium: red Barium: apple green
How do you carry out a
flame test?
- Use a nichrome wire
- Sterilise the wire by dipping in concentrated
hydrochloric acid and then heating in Bunsen flame - Make sure the sample powdered or grinded
- Dip wire in solid and put in Bunsen flame and observe
flame
How are the colours from
the flame test formed?
The heat causes the electron to get excited and thus
move to a higher energy level but at this higher level the
electron is unstable so then moves back down. As it
moves from a higher to lower energy level energy is
emitted in the form of visible light energy which is the
colour you see.
