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WalesChemistry

Unit 2.1 Bonding, structure and properties

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do covalent bonds form, and why do simple molecular substances have low melting points?

Describe covalent bonding as shared pairs of electrons, draw dot-and-cross diagrams for simple molecules, and relate simple molecular structure to low melting points and poor conduction.
A focused answer to WJEC GCSE Chemistry topic 2.1, covering covalent bonding as the sharing of electron pairs between non-metal atoms, drawing dot-and-cross diagrams for simple molecules, and explaining why simple molecular substances have low melting points and do not conduct.
9 min answer →

Why are diamond and graphite so different even though both are made only of carbon?

Describe giant covalent structures including diamond and graphite, and relate their bonding and structure to their very different properties.
A focused answer to WJEC GCSE Chemistry topic 2.1, covering giant covalent structures, the bonding and structure of diamond and graphite, and how these explain their hardness, melting points and electrical conductivity.
8 min answer →

How do ionic bonds form, and why do ionic compounds have such high melting points?

Describe ionic bonding as electron transfer, draw dot-and-cross diagrams for simple ionic compounds, and relate the giant ionic lattice to the properties of ionic compounds.
A focused answer to WJEC GCSE Chemistry topic 2.1, covering ionic bonding as the transfer of electrons between metals and non-metals, drawing dot-and-cross diagrams, the giant ionic lattice, and how the structure explains high melting points and conduction when molten or dissolved.
9 min answer →

How does metallic bonding explain why metals conduct and bend, and why are alloys harder than pure metals?

Describe metallic bonding as positive ions in a sea of delocalised electrons, relate it to metal properties, and explain why alloys are harder than pure metals.
A focused answer to WJEC GCSE Chemistry topic 2.1, covering metallic bonding as positive ions in a sea of delocalised electrons, how this explains conductivity and malleability, and why alloys are harder than pure metals.
8 min answer →

How can we work out the bonding in a substance from its melting point and conductivity?

Use the properties of a substance (melting point, conductivity, state) to deduce its type of bonding and structure.
A focused answer to WJEC GCSE Chemistry topic 2.1, bringing ionic, simple molecular, giant covalent and metallic structures together and showing how to deduce the bonding in a substance from its melting point, electrical conductivity and state.
9 min answer →