Why are titanium and gallium not very similar while lithium and sodium would be most similar ?

Answer 1

Na and Li have one electron in the outside shell so the chemistry is similar. Ti has 2 3d electrons and 2 4s electrons while Ga has 3 electrons in the outside shell so the chemistry is not similar because the electrons are not arranged the same. I wonder if you made a typo and meant to ask about Ge (instead of Ga) since Ge has four electrons also.