Review

2.1. Answers

PART 1: Determine if the elements in the following compounds are metals or non-metals. Describe the type of bonding that occurs in the compound.

PART 2: Use Lewis dot structures to show the ionic bonding in the following pairs of elements. Show the transfer of electrons using arrows. Write the correct chemical formula for the ionic compound that forms.

1. barium oxide (Ba and O)
2. sodium oxide (Na and O)
3. calcium chloride (Ca and Cl)
4. sodium nitride (Na and N)
5. aluminum oxide (Al and O)
6. magnesium phosphide (Mg and P)

PART 3: Use Lewis dot structures to show the covalent bonding in the following pairs of elements. Once you have determined the structure for the molecule, write its structural formula in the space provided; use a dash to represent a shared pair of electrons, and dots to show unshared electrons.

1. nitrogen triiodide (NI₃) HINT: nitrogen is in the middle!
2. carbon tetrabromide (CBr₄) HINT: carbon is in the middle!
3. dihydrogen monoxide (H₂O) HINT: oxygen is in the middle!

Covalent and ionic diagrams

Aim

To practise identifying and drawing covalent and ionic bonding.

 Instructions

Draw the atoms of each of the elements. Then, draw the dot and cross diagram for the molecule those elements could react to form. Work out which bond ionically and which bond covalently.

Carbon and hydrogen

Methane (CH₄)

Potassium and bromine

Potassium bromide

Magnesium and chlorine 

Magnesium chloride

Sulfur and hydrogen

Hydrogen sulphide (H₂S)  

Draw dot cross diagrams for the following substances:

1. Hydrogen gas
2. Chlorine gas
3. Calcium sulfide
4. Oxygen gas
5. Nitrogen gas
6. Hydrogen chloride
7. Carbon dioxide
8. Sodium oxide
9. Ethane
10. Ethene