A molecule is defined as two or more atoms of the same element different element that are bound together. A molecule may be homonuclear, which means, it consists of atoms of one chemical element, as with oxygen (O2); or it may be heteronuclear, a chemical compound composed of more than one element, as with water (H2O).
Answer:

Explanation:
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In this case, since the reaction for the formation of ammonia is:

We can evidence the 1:2 mole ratio of nitrogen gas to ammonia; therefore, the appropriate stoichiometric setup for the calculation of the moles of the latter turns out to be:

And the result is:

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The Calcium atom has 2 valence electrons but a Calcium ion will have no electrons because it is a cation ion. Meaning that there are more protons than electrons. Also, the normal calcium symbol is Ca but the calcium ion is Ca²⁺
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Electrons and protons because they are essentially always the same