Is the correct name for the following compound?
Ca(NO₂)2
The Correct Answer and Explanation is:
The correct name for the compound Ca(NO₂)₂ is Calcium nitrite.
Explanation:
To understand the naming of this compound, we need to break it down into its components based on the principles of nomenclature in inorganic chemistry, specifically following the rules set by IUPAC (International Union of Pure and Applied Chemistry) for naming salts and ionic compounds.
- Calcium (Ca):
- The first part of the compound, Ca, is the symbol for calcium, a metal from the alkaline earth metals group in the periodic table.
- Calcium has a fixed charge of +2 because it typically forms a 2+ ion when it loses two electrons to achieve a stable electron configuration (like the noble gas argon).
- Nitrite (NO₂):
- The second part of the compound is the nitrite ion, which has the chemical formula NO₂⁻.
- Nitrite is an anion (negatively charged ion) derived from nitric acid (HNO₃), but it differs from the nitrate ion (NO₃⁻) by having one less oxygen atom.
- The suffix “-ite” indicates that the compound contains the nitrite ion, as opposed to “-ate,” which would indicate the presence of the nitrate ion.
- Combining the ions:
- The calcium ion (Ca²⁺) combines with the nitrite ion (NO₂⁻) to form the ionic compound calcium nitrite.
- Since calcium has a charge of +2, and each nitrite ion has a charge of -1, two nitrite ions are needed to balance the charge of one calcium ion. Thus, the formula becomes Ca(NO₂)₂.
- Naming convention:
- The cation (positive ion) is named first, followed by the anion (negative ion).
- The metal (calcium) is simply referred to by its name, and the anion (nitrite) is named according to its chemical composition, leading to the name Calcium nitrite.
Thus, Ca(NO₂)₂ is called Calcium nitrite based on its composition and the rules of ionic compound nomenclature.