Why do the names of some ionic compounds include the charge of the metal ion while others do not?

The correct answer is because there are polyvalent metals.

Explanation:

Most transition metals can form cations with various loads. That is why block d of the periodic table is marked as "variable load". For example, iron is polyvalent, which means "many values", i.e. it can form cations with different loads. For polyvalent metals, we must specify the magnitude of the ion charge. In the case of anions most of the time it is not necessary to specify the magnitude of the charge of the anion.

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- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

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