Metals and non-metals.
What is a covalent bond?
A bond formed by the sharing of electron pairs between atoms.
What is a metallic bond?
A bond where positive metal ions are surrounded by a sea of delocalised electrons.
Why is table salt (NaCl) an example of ionic bonding?
NaCl consists of sodium ions (Na⁺) and chloride ions (Cl⁻) held together by ionic bonds.
Electrostatic attraction between oppositely charged ions.
How is a double bond different from a single bond?
A double bond shares two pairs of electrons, while a single bond shares one.

Why are metals good conductors of electricity?
The delocalised electrons are free to move and carry charge.
Why is water a liquid at room temperature while carbon dioxide is a gas?
Water has strong intermolecular forces, while carbon dioxide has weaker intermolecular forces.

Why do ionic compounds have high melting points?
Strong electrostatic forces between ions require a lot of energy to break.
Why are covalent compounds typically poor conductors of electricity?
They don’t have free electrons or ions to conduct electricity.
Identify the role of delocalized electrons in a metallic structure.

The delocalized electrons enable electrical conductivity by moving freely throughout the structure.
Why is copper used in electrical wiring?
Copper’s metallic bonds allow free electrons to move and conduct electricity.
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Explain what happens when sodium and chlorine form an ionic bond.

Sodium loses one electron to form Na⁺, and chlorine gains it to form Cl⁻.
Which of the following pairs of elements can form a covalent bond?
A. sodium and oxygen
B. magnesium and oxygen
C. hydrogen and chlorine
D. magnesium and chlorine
C. hydrogen and chlorine

A cube has a side length of 0.2cm. What is the volume of the cube?
The volume of the cube is 0.008 cm3.

How do the properties of metals explain why they are used in making bridges?
Metals are strong, ductile, and malleable due to metallic bonding, making them ideal for construction.

What statement describes the structure of sodium chloride?
The ions are arranged in a regular lattice.

Give an example of a molecule that forms a double bond.
Oxygen (O₂) forms a double bond.

How does alloying a metal affect its properties?
Alloying disrupts the regular arrangement of metal atoms, often increasing strength and hardness.

Complete the sentence: Ionic compounds can conduct electricity when...
...dissolved in water or molten.