Question

part 2: multiple choice - circle the correct answer

1. which of the following is an example of a nonpolar covalent molecule?

a) nacl c) o₂
b) h₂o d) hf

1. which type of bond conducts electricity when dissolved in water?

a) polar covalent c) ionic
b) nonpolar covalent d) metallic

1. a molecule that starts with hydrogen and ends with a nonmetal most likely has

a) nonpolar covalent bond c) polar covalent bond
b) ionic bond d) hydrogen bond

1. which of the following would most likely form an ionic bond?

a) carbon and oxygen
b) sodium and chlorine
c) nitrogen and hydrogen
d) fluorine and fluorine

Explanation:

1. Non - polar covalent molecules occur when electrons are shared equally between atoms. In $O_2$, two oxygen atoms share electrons equally. $NaCl$ is ionic, $H_2O$ and $HF$ are polar covalent.
2. Ionic compounds dissociate into ions in water and can conduct electricity. Polar and non - polar covalent compounds do not dissociate into ions easily to conduct electricity in water, and metallic bonds are not relevant in solution.
3. A molecule starting with hydrogen and ending with a non - metal often has a polar covalent bond due to the difference in electronegativity between hydrogen and the non - metal.
4. Ionic bonds form between a metal and a non - metal. Sodium is a metal and chlorine is a non - metal, while the other pairs are non - metal combinations (covalent bonds in most cases).

Answer:

1. c) $O_2$
2. c) Ionic
3. c) Polar covalent bond
4. b) Sodium and chlorine