Question

1. which noble gas does not follow the octet rule?

argon
helium
krypton
neon

1. for period 1 and 2, what is the maximum number of valence electrons an element can have?

2
4
6
8

Explanation:

1. The octet rule states that atoms tend to have 8 electrons in their valence shell for stability. Helium has only 2 electrons in its single - electron shell and follows the duet rule instead of the octet rule. Argon, Krypton, and Neon have full outer shells of 8 electrons and follow the octet rule.
2. In period 1, the maximum number of electrons in the outer shell (valence electrons) is 2 (for hydrogen and helium). In period 2, the maximum number of valence electrons an element can have is 8. So overall for periods 1 and 2, the maximum is 8.

Answer:

1. B. Helium
2. D. 8