1.1. A student was investigating a calcium salt labelled Y.

The student found that Y:

• has a very high melting point

• does not conduct electricity

• is water soluble and the solution produced conducts electricity

What type of bonding is present in salt Y?

1.2. Explain why the solid Y does not conduct electricity but its aqueous solution does.

1.3. Figure 1 shows the bonding arrangement of an element. 

Figure 1

What is the element? 

Tick (✔) one box.

1.4. The image in Figure 1 is an allotrope. 

Why does this allotrope conduct electricity? 

1.5. Figure 2 shows the particle diagram of an alloy. 

Figure 2

Explain why this alloy is harder than pure metal Y.

1.6. What kind of substances are alloys?

Tick (✔) one box.