Periodicity is the repeating trends in the properties of the elements across a period. The properties that show trends include electron configuration, ionisation energy, structure and melting points.Period 3 Elements in groups 1, 2 and 3 are metals. The elements in group 1, 2 and 3 lose their outer electrons to form positive ions. They exist as giant metallic lattices.Group 5, 6 and 7 are non-metals phosphorus, sulfur and chlorine. They accept electrons to form ionic compounds or share electrons to form covalent compounds.Argon is in group 0 and is an inert noble gas with a full outer shell.
Periodicity and Period 3 Elements
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Specification: AQA Chemistry (7404), AS-level, 3.2.1.2 Physical properties of Period 3 elements. Topic: Periodicity.
Key terms in this lesson
- Electron configuration
- The arrangement of electrons in an atom's shells and sub-shells, written using numbers and letters such as 1s2 2s2.
- Periodicity
- The repeating trend in the properties of elements across each period of the periodic table.
- Group
- A vertical column of the periodic table, containing elements with the same number of outer-shell electrons.
- Period
- A horizontal row of the periodic table, containing elements with the same number of electron shells.
More in Periodicity
- Groups
- Periods
- Reactivity
- Hydrogen and Helium
- Trends in Melting and Boiling Points
- Atomic Radii
- First Ionisation Energy
- Group 2 and 3
All 14 lessons in Periodicity · All AQA AS-level Chemistry topics