1. The electronic configuration of chlorine is 1. 2,7
II. 2,8,8,7
III. 2,8,7
IV. 2,7,8
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Chlorine has atomic number 17. Its electronic configuration is 2, 8, 7. It is the second-lightest of the halogens, it appears between fluorine and bromine in the periodic table.

III

Explanation:

From the periodic table, Chlorine(Cl) has 17 protons.

And when arranging the proton of elements each shell has a number protons it can take, i.e

2,8,8,8

The first shell can only take a maximum of 2 protons while the second shell upwards takes a maximum of 8 protons

Now we want to arrange Chlorine;

1st shell = 2

2nd shell = 8

2 + 8 = 10

17(no. of Chlorine protons) - 10

= 7

therefore,

3rd shell = 7

Therefore,

The electronic configuration of chlorine is

2,8,7

fe 55.85 g/mol and h2o 18.02 g/mol.