2.4 - Period 3 Elements

Question 1

Appearance and physical properties of sodium?

Answer 1

• Metallic
• Shiny
• Conducts electricity

Question 2

Reaction of sodium with acid?

Answer 2

Na + acid -> H2 + salt

Question 3

Reaction of sodium with cold water - equation + observations?

Answer 3

Vigorous reaction, floats on water, fizzes, melts due to -ΔH of the reaction. NaOH is pH 13-14.
2Na + 2H2O –> 2NaOH + H2

Question 4

Reaction of sodium with oxygen (equation + observations)?

Answer 4

Bright yellow flame, forms white powder of Na2O
2Na + 1/2O2 –> Na2O

Question 5

Appearance and physical properties of Mg?

Answer 5

• Metallic
• Shiny
• Conducts electricity

Question 6

Reaction of Mg with cold water (observations and equation)?

Answer 6

Very slow reaction.
pH = 10 as Mg(OH)2 is sparingly soluble
Mg + 2H2O —> H2 + Mg(OH)2

Question 7

Reaction of Mg with steam (observations and equation)?

Answer 7

Much faster
Mg + H2O —> MgO + H2

Question 8

Reaction of Mg with oxygen (observations and equation)?

Answer 8

Bright white flame, forms white powder of MgO
2Mg + O2 —> 2MgO

Question 9

Appearance and physical properties of aluminium?

Answer 9

• Metallic
• Shiny
• Best metal conductor in p3

Question 10

Reaction of Al with cold water?

Answer 10

No reaction

Question 11

Reaction of Al with oxygen (equation and observations)?

Answer 11

Heat and lower into jar of O2 –> bright flame, forms white powder
4Al + 3O2 —> 2Al2O3