Chemistry

Question 1

1Ionic compounds conduct electricity when

Easy

A. solid B. molten or dissolved in water C. powdered D. cold

Question 2

2Graphite conducts electricity because it has

Easy

A. hydrogen bonds B. ions that move C. delocalised electrons between its layers D. no bonds

Question 3

3Diamond is very hard because

Easy

A. its molecules are small B. it has free electrons C. it is made of ions D. each carbon atom is covalently bonded to four others in a giant structure

Question 4

4Different forms of the same element in the same physical state are

Easy

A. allotropes B. isomers C. isotopes D. homologues

Question 5

5Simple molecular substances such as CO₂ have

Easy

A. low melting and boiling points B. ionic bonds C. metallic lustre D. very high melting points

Question 6

6Sodium chloride has a high melting point because

Hard

A. it is covalent B. it has delocalised electrons C. strong electrostatic forces hold the giant ionic lattice D. it has weak van der Waals forces

Question 7

7Metals conduct electricity because they have

Easy

A. ions that move in the solid B. delocalised electrons C. covalent bonds D. no electrons