Atomic Theory — Unit test Answers

Two red and two overlapping balls in the center are surrounded by a green, fuzzy, circular cloud with a white line running through it. Two green balls sit on the white line, and a line leading a bracket around the balls is labeled A. A line leading to a bracket overlapping the white line is labeled B.

Which is the electronic configuration for oxygen?

Which are different forms of an element that have different numbers of neutrons?