Chapter 6, Problem 7PE

Interpretation Introduction

Interpretation:

The formulas of chromium(III) fluoride and sodium sulfide are to be written.

Concept introduction:

Mostly, the elements are found as single atom particles in the universe. For example, the element which exists in the gas phase as single atoms at temperatures is Helium. When atom accepts or loses electrons it is termed as ion. If the ion loses an electron and accepts a positive charge it is called as cation. Similarly, if the ion gains an electron and accepts a negative charge it is called an anion. When the ion is formed from a single atom, it is referred as monatomic ion. But, in nature, many compounds are found as polyatomic ions (poly = many). Polyatomic ions are electronically neutral, for example, ammonium ion will not exist without its counter negative ion. In general, formulas of ionic compounds depict the ratio of positive and negative ions found in a substance. Moreover, the formulas of compounds are made up of lowest whole number ratio of ions i.e., formula unit. Notably, the number of positive units and the number of negative units will be equal in a chemical formula.