Respuesta :
When chlorine forms an ion it gains an electron and has an octet in its outer shell. The correct answer is A.
What happens when chlorine form an ion is that it gains an electron and has an octet in its outer shell ( answer A)
Explanation
Chlorine is is in atomic number 17 in periodic table.
The electron configuration of chlorine is 1S2 2S2 2P6 3S2 3P5 or[Ne]3S2 3p5 or 2.8.7.
chlorine therefore has 7 valence electron therefore it gain 1 electron to form Cl- ( ion)
Cl- has 8 electron in its outer shell ( it obeys octet rule of eight valence in outer shell.