Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 2.1.2 Group 1: Reactivity & Electronic Configurations

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Edexcel IGCSE Chemistry 復(fù)習(xí)筆記 2.1.2 Group 1: Reactivity & Electronic Configurations

Group 1: Reactivity & Electronic Configurations

The reactivity of the group 1 metals?increases?as you go down the group
When a group 1 element reacts its atoms only need to lose electron, as there is only 1 electron in the outer shell
- When this happens, 1+ ions are formed
The next shell down automatically becomes the outermost shell and since it is?already full,?a group 1 ion obtains?noble gas configuration
As you go down group 1, the number of shells of electrons increases by 1
- This means that the outermost electron gets?further?away from the nucleus, so there are?weaker?forces of attraction?between the outermost electron and the nucleus
- Less energy?is required to overcome the force of attraction as it gets weaker, so the outer electron is lost?more easily
- So, the alkali metals get more reactive as you descend the group

Electronic-configuration-of-Li-Na-and-K

These electron shell diagrams of the first 3 alkali metals show that the group 1 metals have 1 electron in their outer shell

Exam Tip

In your exams, you could be asked to explain the trend in reactivity of the alkali metals - make sure you answer this question using their electronic configuration to support your answer.

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