Introduction

This section covers the arrangement of electrons (electronic configurations) in quantum shells (orbitals). This topic moves far beyond IGCSE and describes the trends which underlie the periodic table. Links to quantum physics are found here as the energy level of each electron is considered. Electronic configuration determines the chemical properties of each element. Although this sounds complicated it is very logical and the periodic table will help you work out the electronic configuration of each element so keep it to hand.

Reading

Edexcel AS/A Level Chemistry Student Book 1 pages 16 to 23, pages 30 to 32

Tasks

Complete the following:

Read pages 16 to 23, making appropriate notes (include key definitions).
Complete the ‘in-text’ questions.
Draw simple diagrams to represent electron density maps.

WATCH – Electronic Configuration (YouTube)

REVIEW – Filling Electron Levels (PowerPoint)

COMPLETE – Gridlocks: Atomic Structure (RSC)

COMPLETE – Gridlocks: Sub-atomic Particles (RSC)

COMPLETE – Gridlocks: Sub-shells (RSC)

Read Elemental Fingerprints, pages 30 to 31, and answer the questions.

COMPLETE – Worksheet 5

Check your answers.

REVIEW – Answers to Worksheet 5

Complete questions 4 and 5 on page 32.

Top Tips

Make sure that you understand the following key points:

Check all electronic configurations you complete against your Periodic table.
Remember Hund’s rule and the Pauli Exclusion Principle. This will ensure that you are confident filling in “box” displays of electronic configurations which are so popular in examinations.

Key Terms

Add the following subject vocabulary with definitions to your glossary.

Quantum shell
Orbital
Hund’s rule
Electronic configuration
Pauli exclusion principle