End of Unit Test (Chemical Bonding)

Student Bio Data

Student name

Class / Group

Teacher

Date

1. Short answers [5]

a) Why does an oxygen atom share two pairs of electrons rather than just one? b) Describe how a potassium atom becomes a potassium ion. c) Why is there a bond between the ions in potassium chloride? d) Solid potassium chloride is a poor conductor of electricity. When dissolved in water it is a good conductor. Explain.

2. Melting/Boiling & Electrical properties [6]

a) Which two substances could be metals? b) Which substance could be nitrogen? c) Which substance could be an ionic compound? d) Which substance is a liquid at room temperature? e) Which could be giant covalent (like diamond)? f) Which two could exist as simple covalent molecules?

3. MCQ – Which compounds are covalent? [1]

A. 2 and 3 B. 2 and 4 C. 1, 2 and 3 D. 1 and 4

4. MCQ – What change occurs when an atom forms a negative ion? [1]

A. It loses electrons. B. It gains protons. C. It gains electrons. D. It loses protons.

5. Structures A–E [3]

a) Which two of these structures are covalently bonded? b) Which one of these structures is a diatomic molecule?

Score: ____ / 16

Click Mark Now to auto-mark. Partial credit is awarded on multi-part and short-answer items.