The Periodic Table and Electronic Structure

IGCSE Edexcel Chemistry
1.18–1.24 Periodic Table and Trends
Key Concept: Elements are arranged by atomic number in periods and groups. Elements in the same group have similar properties because they have the same number of outer-shell electrons.

Section A: Arrangement and Classification

1. Describe how the periodic table is arranged and define period and group. [4]
2. Use electrical conductivity and oxide character to classify each element as metal or non-metal. [4]
Element Conducts electricity? Oxide type Classification
Element A Yes Basic oxide
Element B No Acidic oxide

Section B: Electronic Configuration

3. Write the electronic configuration for each element (first 20 only). [6]

a) Sodium (Na, 11)

b) Magnesium (Mg, 12)

c) Chlorine (Cl, 17)

4. Determine the group and period for each electronic configuration. [6]

a) 2,8,1

b) 2,8,7

c) 2,8,8,2

Section C: Group Trends

5. Explain why elements in the same group have similar chemical properties. [2]
6. Explain why noble gases are unreactive. [2]

Total: [24 marks]

Mark Scheme

1. Ordered by atomic number [1]; periods are rows [1]; groups are columns [1]; elements in group share similar properties [1]
2. A: metal [2]; B: non-metal [2]
3. Na: 2,8,1; Mg: 2,8,2; Cl: 2,8,7 (1 mark each) [6]
4. 2,8,1 → Group 1 Period 3 [2]; 2,8,7 → Group 7 Period 3 [2]; 2,8,8,2 → Group 2 Period 4 [2]
5. Same number of outer-shell electrons so similar bonding and reactions [2]
6. Full outer electron shells, stable, do not readily gain/lose/share electrons [2]