The behaviour of lithium is similar to that of magnesium. This sort of similarity is commonly referred to as:

Explanation

The resemblance between lithium and magnesium is a diagonal relationship: lithium lies in Period 2, Group 1 and magnesium diagonally below it in Period 3, Group 2. Similar ionic sizes and charge-to-radius behaviour account for several shared properties. They are not isoelectronic neutral atoms.