Introduction to calcium reactivity
Calcium has only one nonzero oxidation state. As shown at the right elemental calcium can only act as a reductant (electron donor) to form Ca2+. Calcium exists as Ca2+ in ALL of its compounds.
When calcium or another Group 2 element reacts as a reductant with a nonmetal. The nonmetal becomes negative, the exact charge depending on its group.
 reductant | +2 | Ca2+ |
| 0 | Ca |
When calcium or another Group 2 element reacts as a reductant with a nonmetal. The nonmetal becomes negative, the exact charge depending on its group.
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Furthermore the overall charge on the product of the reaction of two elements must be zero.
These ideas can be applied to deduce a plausible formula for the product of reaction of elemental calcium with a metallic and a nonmetallic element.
When calcium or another Group 2 element acts as a reductant toward a compound, an atom in the compound in a positive oxidation state accepts electrons.
These ideas can be applied to deduce a plausible formula for the product of reaction of elemental calcium with a metallic and a nonmetallic element.
Consider the reaction between calcium and elemental nitrogen.
In the product calcium must be Ca(+2), nitrogen is likely to be N(-3)
The formula of the product could be predicted to be Ca3N2 (which in fact is the compound formed).
In the product calcium must be Ca(+2), nitrogen is likely to be N(-3)
The formula of the product could be predicted to be Ca3N2 (which in fact is the compound formed).
When calcium or another Group 2 element acts as a reductant toward a compound, an atom in the compound in a positive oxidation state accepts electrons.