Which element has chemical properties that are most similar to the chemical properties of sodium?

(1) beryllium (3) lithium

(2) calcium (4) magnesium

Check out your periodic table. Elements in the same column (families) usually share similar properties because they have the same number of valence electrons. In this case, the only element listed that is part of Sodium's family is Lithium, so Lithium is most similar to Sodium.