Consider the electron configuration. A box holds an up and a down arrow. A box holds an up and a down arrow. A box holds an up and a down arrow.A box holds an up and a down arrow.A box holds an up and a down arrow. A box holds an up and a down arrow. A box holds an up and a down arrow.A box holds an up and a down arrow.A box holds an up arrow. 1s 2s 2p 3s 3p Which element has this electron configuration? astatine bromine chlorine fluorine
Each arrow represents one electron. Most of the boxes are filled, meaning they have two electrons. The last box only has one arrow, so it only has one electron. If you add it up, you get 17, which is Chlorine.