Chemical bonding and structure

Explain G3 Science Chemistry ionic and covalent bonding, connect structures to properties, and choose metals and alloys for their uses.

Before you begin

Explain G3 Science Chemistry ionic and covalent bonding, connect structures to properties, and choose metals and alloys for their uses.

Learning goals

Describe how atoms lose or gain electrons to form ions, which usually have a noble-gas electronic configuration
Describe ionic bonding between metals and non-metals, such as in NaCl and MgCl₂, using dot-and-cross diagrams
Describe a covalent bond as a shared pair of electrons, with the bonded atoms usually reaching a noble-gas electronic configuration
Draw dot-and-cross diagrams for covalent bonds between non-metals, such as in H₂, O₂, H₂O, CH₄ and CO₂
Deduce the electron arrangement in other covalent molecules
Relate the physical properties of ionic compounds, including electrical conductivity, to their lattice structure
Relate the physical properties of covalent substances, including electrical conductivity, to their structure and bonding
Describe how elements, compounds and mixtures differ
Describe the typical physical properties of solid metals: high melting and boiling points, malleability and good conduction of heat and electricity
Describe an alloy as a mixture of a metal with another element, such as brass or stainless steel
Recognise metals and alloys in structure diagrams

Syllabus statements covered

describe the formation of ions by electron loss/gain and that these ions usually have the electronic configuration of a noble gas
describe, including the use of ‘dot-and-cross’ diagrams, the formation of ionic bonds between metals and non-metals, e.g. NaCl; MgCl2
relate the physical properties (including electrical property) of ionic compounds to their lattice structure.
describe the formation of a covalent bond by the sharing of a pair of electrons and that the atoms in the molecules usually have the electronic configuration of a noble gas
describe, using ‘dot-and-cross’ diagrams, the formation of covalent bonds between non-metallic elements, e.g. H2; O2; H2O; CH4; CO2
deduce the arrangement of electrons in other covalent molecules
relate the physical properties (including electrical property) of covalent substances to their structure and bonding.
describe the differences between elements, compounds and mixtures
describe the general physical properties of metals as solids having high melting and boiling points, malleable and good conductors of heat and electricity
describe an alloy as a mixture of a metal with another element, e.g. brass; stainless steel
identify representations of metals and alloys from diagrams of structures.

Work through them in order.

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