Group 2 Flashcards
Why don’t some atoms give results in the flame test?
They give out light outside the visible spectrum
The Bunsen burner might not provide enough energy
What is a flame photometer?
This can be used to measure quantitively the wavelengths given out by ions by analysing the flame produced
It’s much more accurate
Why do group 2 metals become harder to ignite as you go down the group?
They form an oxide layer which stops it igniting
What is observed when group 2 metals react with oxygen?
A bright white light
What is the general equation for when group 2 metals react with oxygen?
2M(s) + O2 (g) –> 2MO (s)
What is the general equation for the reaction between group 2 metals and chlorine?
M(s) + Cl2 (g) –> MCl2 (s)
What is the general equation for the reaction between group 2 metals and water?
M(s) +2H20 (l) –> M(OH)2 (aq) + H2
What is the general equation for the reaction between group 2 metal oxides and water?
MO(s) + H2O (l) –> Mg(OH)2 (aq)
What can be observed when group 2 metals react with water?
Turn pH paper alkali
Vigorous effervescence
Magnesium reacts very slowly
Beryllium doesn’t react due to the thick oxide layer
What is the equation for the reaction between magnesium and steam?
Mg(s) + H2O (g) –> H2 (g) + MgO (s)
White solid and bright white light
What can be observed when metal oxides react with water?
Solid remains, showing not completely soluble
Heat
Alkali solution
Solubility increased down the group
What is the general equation for the reaction between group 2 metal oxide and water?
MO(s) + H2O (l) –> Mg(OH)2 (aq)
What causes the colour in the flame test?
Excited electrons emit light when they fall to their ground state
Each element has its own characteristic energy levels
Check markscheme
How does solubility change down group 2 nitrates?
Decreases
What is the general equation for the reaction between group 2 metal oxides and HCl and nitric acid?
MO(s) + 2HCl –> MCl2 (aq) + H2O
MO(s) + 2HNO3 –> M(NO3)2 (aq) + H2O