Mistakes made in papers

Question 1

When talking about nuclear attraction on electrons what do you always include?

Answer 1

atomic radius - More shells means bigger atomic radius thus less attraction.

Question 2

What is atomic number?

Answer 2

The number of protons in the nucleus an element has.

Question 3

State the blocks in the periodic table (in terms of s,p,d and f).

Answer 3

Question 4

Draw water molecules in hydrogen bonding.

Answer 4

Question 5

Why does chlorine displace iodine ions?

Answer 5

• Chlorine is more reactive
• Chlorine is a more powerful oxidising agent.

(Not that it is more electronegative!)

Question 6

Draw the hydrogen bonding between ammonia molecules.

Answer 6

Remember:

• Lone pair
• Only one hydrogen bond per 2 nitrogen molecules

Question 7

Write out the reaction for chlorine with concentrated sodium hydroxide, were one of the products is NaClO₃.

Answer 7

3Cl₂ + 6NaOH —-> NaClO₃ + 5NaCl + 3H₂O

Question 8

A student adds a sample of solid potassium carbonate, K₂CO₃ , to an excess of dilute sulfuric acid.

Describe what the student would see and write the equation for the reaction which takes place.

Answer 8

K₂CO₃ + H₂SO₄ —> K₂SO₄ + H₂O + CO₂

• Bubbling from reaction mixture
• The potassium carbonate would dissolve into the solution.