Question

What is an element that shares group properties with Mg? What properties are common in this group?

Answer 1

Lithium (Li) shares group properties with Magnesium (Mg). This is due to the diagonal relationship present in the periodic table.

It is found that the chemistry of a first-row (second period) element often has similarities to the chemistry of the second-row (third period) element being one column to the right of it in the periodic table. Thus, the chemistry of Li has similarities to that of Mg,

The properties that are common in between this two elements are

1. Both Lithium and Magnesium forms normal oxides on reaction with oxygen (They won't form any superoxides).

2. Like Mg, Li is the only Group 1 element which forms a stable nitride, Li₃N.

3. Both Li and Mg form covalent organometallic compounds, in contrast, another group 1 and 2 elements form ionic compounds. For example, Li forms alkyl lithiums like MeLI, BuLi. Mg forms RMgX type organometallic reagent (Grignard reagent).

4. Chlorides of both the elements (Li, Mg) are LiCl and MgCl₂ can absorb moisture from surroundings (moisture sensitive). Both on reaction with water forms crystal and can be separable. LiCl forms LiCl.2H₂O whereas MgCl₂ forms MgCl_2.6H₂O.