CHEMISTRY DEPARTMENT WAID ACADEMY

1. CHEMISTRY DEPARTMENT WAID ACADEMY BONDING AND PROPERTIES

2. 30 Which of the following chlorides is likely to have the least ionic character? • CsCl. • CaCl2. • LiCl. • BeCl2.

3. 20 Which type of structure is found in a substance melting at 811oC which conducts electricity when molten, but not when solid? • Covalent molecular. • Covalent network. • Ionic. • Metallic.

4. 20 In which of the substances, in the solid state, would van der Waal's forces be a significant "intermolecular force"? • Sodium chloride. • Carbon dioxide. • Magnesium. • Ice.

5. 20 The melting point of the group 7 elements increase on descending the group because the • covalent bond lengths increase. • electronegativity values decrease. • van der Waal's attractions increase. • nuclear charges increase.

6. 20 Tetrachloromethane, CCl4, is considered to be a non-polar substance because • the polar bonds are arranged symmetrically. • the C-Cl bonds are non-polar. • a covalent network structure exists. • only linear molecules are polar.

7. 20 In which of the following molecules does hydrogen bonding exist? • CH4. • PH3. • H2S. • NH3.

8. 20 Graphite, a form of carbon, conducts electricity because it has • metallic bonding. • van der Waal's forces. • delocalised electrons. • pure covalent bonding.

9. 15 Which type of bonding can be described as intermolecular? • Hydrogen. • Covalent. • Metallic. • Ionic.

10. 20 Which oxide would be a solid at room temperature (20oC) and a gas at 325oC?You may wish to refer to the data booklet. • Fluorine oxide. • Phosphorus oxide. • Magnesium oxide. • Boron oxide.

11. 15 Which of the substances shown below is covalent molecular? • Carbon (graphite). • Carbon (fullerine). • Carbon (diamond). • Silicon.