posted by Paul .
Write the electron configuration for the following ground state atoms and ions. strontium+2 ion; iron element; selenium -2 ion; gallium +3 ion; and tin element.
There must be something about this that is giving you trouble. Here is a web site from which you an get all of the answers but you need to know how to do it yourself. The filling order is 1s 2s 2p 3s 3p 4s 3d etc.
An chemistry is spelled correctly here.