Periodic Table — Part 2: Periodic properties and two families: visual lesson, ICSE Class 10 Chemistry (Science Paper 2)

Lesson

Patterns you can predict

Part 2 — the same two factors (nuclear charge and shells) explain how easily atoms lose or gain electrons, and so how reactive they are.

In this lesson you will

Relate metallic and non-metallic character to losing and gaining electrons
Define ionisation potential, electron affinity and electronegativity and describe their trends
Compare the reactivity of lithium, sodium and potassium
Explain why the reactivity of halogens decreases down the group

Concept

Metallic and non-metallic character

Metallic character is the tendency of an atom to lose electrons and form a positive ion; non-metallic character is the tendency to gain electrons and form a negative ion. Across a period, metallic character decreases and non-metallic character increases (the nucleus holds electrons more tightly). Down a group, metallic character increases (outer electrons are held less tightly).

Table of period 3 elements showing the change from metal to non-metal and from basic to acidic oxides
Period 3	Na	Mg	Al	Si	P	S	Cl
Character	Metal	Metal	Metal	Metalloid	Non-metal	Non-metal	Non-metal
Oxide	Basic	Basic	Amphoteric	Acidic	Acidic	Acidic	Acidic

Check your understanding

Quick check: metal or non-metal?

Use position in the table to compare metallic character.

Question: Multiple choice

Multiple choice1 mark

Which element has the most metallic character?

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