FOCUS ON: Covalent Bonding

Part 1 - Keywords:

1. Covalent bonding

2. Molecules

3. Polymers

4. Giant covalent structures

5. Diamond

6. Silicon dioxide

7. Dot and cross diagrams

8. Covalent bonds

Part 2 - Key Facts:

1. Covalent bonding occurs when atoms share pairs of electrons to form bonds.

2. Some covalently bonded substances consist of small molecules, while others form giant covalent structures.

3. Substances with very large molecules, like plastics, are examples of covalently bonded polymers.

4. Giant covalent structures include substances such as diamond (carbon) and silicon dioxide (silica).

5. Covalent bonds in molecules and giant structures are strong and hold the atoms together.

6. Dot and cross diagrams are used to represent covalent bonds, illustrating the sharing of electron pairs between atoms.

Part 3 - Quick Quiz:

1. What type of bonding involves the sharing of electron pairs between atoms?

   a) Ionic bonding

   b) Metallic bonding

   c) Covalent bonding

   Answer: c) Covalent bonding

2. Which substance is an example of a giant covalent structure?

   a) Sodium chloride

   b) Water (H₂O)

   c) Diamond (C)

   Answer: c) Diamond (C)

3. How are covalent bonds represented in dot and cross diagrams?

   a) By circles and squares

   b) By arrows pointing towards each other

   c) By shared pairs of electrons

   Answer: c) By shared pairs of electrons

Part 4 - Going Further:

Question: Explain the differences between substances with covalently bonded molecules and those with giant covalent structures.

Answer: Substances with covalently bonded molecules, like water (H₂O) and methane (CH₄), consist of small, discrete units held together by covalent bonds. In contrast, substances with giant covalent structures, such as diamond (C) and silicon dioxide (SiO₂), have a network of covalent bonds extending throughout the entire structure. While covalently bonded molecules have specific formulas and molecular structures, giant covalent structures lack distinct molecules and exhibit extensive bonding throughout the material.

Part 5 - Revision Tips:

To understand covalent bonding, practice drawing dot and cross diagrams to represent the sharing of electron pairs between atoms. Compare the structures of covalently bonded molecules and giant covalent structures to recognise their differences.

Part 6 - More Help:

Stay tuned for the next issue, where we'll explore another intriguing topic in GCSE Science.