Work Step by Step
The number of protons is what defines what an element is, so 34 protons means that the element is selenium. The number in the upper left hand corner, which for the Cobalt ion is 59, is the sum of protons and neutrons. Since cobalt has to have 27 protons, that means that there have to be 32 neutrons. The number in the top right is the charge, which is the difference between protons and electrons. Since for cobalt it is 3+, that means that there are three more protons than electrons. Repeat this thought process for the other ions.