Question

chemical bonds 1 quiz (graded) - 10 questions
6 an atom has 15 total electrons. how many electrons does it have in its outer shell?
a three
b four
c five
d six

Explanation:

Step1: Recall electron - shell filling rules

Electrons fill shells in a specific order: the first shell can hold a maximum of 2 electrons, the second shell can hold a maximum of 8 electrons, and the third shell starts to fill after the first two are full.

Step2: Distribute 15 electrons among shells

The first shell takes 2 electrons, the second shell takes 8 electrons. So far, 2 + 8=10 electrons are accounted for. The remaining 15 - 10 = 5 electrons go into the third (outer) shell.

Answer:

C. Five