Drawing diagrams of electronic configurations

3 marks · Normal

Explain why the electronic configuration of neon is considered stable. Refer to its atomic number and how electrons are arranged in its shells.

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Neon has an atomic number of 10, so it has 10 electrons. Its electrons are arranged as 2 in the first shell and 8 in the second shell, filling both shells completely. Atoms with full outer shells are stable and unreactive.

Must show: Neon has 10 electrons, Arranged as 2,8, Full outer shell, Stability linked to filled shells

Also accept: Mentions 2,8 arrangement and full shells; Explains that outer shell being full causes stability

Common mistakes: States only number, not arrangement; Does not mention outer shell

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Marking points

M1 · 1 mark · States atomic number of neon = 10 electrons.

A1 · 1 mark · Gives correct shell arrangement: 2 electrons in first shell, 8 in second shell.

E1 · 1 mark · Explains stability: full outer shell means neon is stable/unreactive.

Worked solution

Neon's atomic number is 10, so it has 10 electrons.

First shell is filled with 2 electrons, second shell filled with 8 electrons (2, 8).

A full outer shell (the second shell having 8 electrons) makes the atom stable and unreactive.