What are elements made up of

Iam in desperate need of with this !

Ican determine the molar mass of an element by looking on the under the atomic mass for the element. for example the molar mass of phosphorus is 30.974 grams/mole. avogadro’s number tells me the amount of representative particles in 1 mole of any substance. this means 12.011 gram sample of carbon and a 32.0 gram sample of sulfur have the same number of atoms.

What is the compound name for the formula [ru(en)2cl2]2+ and [co(en)cl2br]-