Why is argon an unreactive element?

Neon is an unreactive element in the same group of the Periodic Table as argon, but in Period 2. It has an atomic number of 10.

Deduce the electronic configuration of neon.

• A 2.8
• B 2.6
• C $\mathrm{2.8.2}$
• D 2.2

Calcium reacts with chlorine to form the ionic compound calcium chloride (${CaCl}_2$).

Describe, in terms of electrons, how an atom of calcium reacts with two chlorine atoms to form calcium chloride.

Write the formula of a calcium ion.

In the reaction between calcium and chlorine, both oxidation and reduction occur.

Which row shows the element that is oxidised and the element that acts as the reducing agent in this reaction?

A student uses a flame test to distinguish between separate samples of lithium chloride and copper(II) chloride.

This is the student's method.

There is one mistake in step 1 and one mistake in step 3.

• step 1 dip a nichrome wire into some concentrated sulfuric acid
• step 2 dip the nichrome wire into the sample
• step 3 place the wire and sample into a luminous Bunsen flame
• step 4 record the colour of the flame

Describe a correct method for step 1 and step 3.

• step 1:
• step 3:

What colour is the flame when the test on lithium chloride is carried out correctly?

• A yellow
• B lilac
• C green
• D red