A student is studying the ways that different elements are similar to one another. Diagrams of atoms from four different elements are shown above. Which two atoms are of elements in the same group of the periodic table?
On each group, the number of atoms on the outer shell is always the same as the number of the group. In atom 1 and Atom 4 there is 4 electrons on the outer shell, meaning that they are both in group 4.
