Question

A student explained to the class that helium has 8 valence electrons because it is in group 18. Is the student correct?

- The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. 
- The student is correct because all elements in group 8 have a full outer energy shell. 
-The student is correct because all elements in group 18 have 8 valence electrons. 
-The student is incorrect because all noble gases have 2 valence electrons.

Answer 1

The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. Although helium is placed in Group 18 which generally has 8 valence electrons, it does not have 8 valence electrons as the student suggested. It was grouped together with the noble gases because it exhibits similar properties with them.