Electronic configuration
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 4 worked examples, 7 practice questions, 1 real past-paper question with the answer explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Why electrons matter
- How many electrons in each shell?
- How to write a configuration
Read the transcript of the teaching part
Last time
Before we start: last time, in Covalent bonding and giant covalent structures, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Why electrons matter
Sodium is soft and explosive in water. Argon will not react with anything. Both are atoms made of the same three particles. The difference is how their electrons are arranged, and that arrangement is called the electronic configuration.
How many electrons in each shell?
Electrons are found in shells around the nucleus, and each shell can hold only a certain number. The first shell, closest to the nucleus, holds a maximum of two electrons. The second shell holds a maximum of eight. And for the first twenty elements, the third shell holds a maximum of eight as well.
How to write a configuration
First, find the number of electrons. For a neutral atom, it is equal to the proton number. Second, fill the first shell with two electrons. Third, fill the second shell with up to eight, and then the third with up to eight. Fourth, put any left over in the next shell, and write the numbers separated by commas.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Electronic configuration.
The whole chapter: Atoms, Elements and Compounds, Atoms, Elements and Compounds.
Chapter 2: Atoms, elements and compounds
- Atoms: protons, neutrons and electrons 6 min
- Isotopes and relative atomic mass 7 min
- Electronic configuration 5 min
- Ionic bonding 6 min
- Covalent bonding and simple molecules 6 min
- Giant covalent structures 6 min
- Metallic bonding 6 min
- Comparing structures and properties 7 min
Also for IGCSE Chemistry 0620
Which topics come up most in IGCSE Chemistry 0620 past papers, counted from every paper since 2004.