US - Science - Chemistry

In chemistry contexts, “mass of NaCl (Sodium chloride)” almost always refers to its molar mass. Sodium chloride (NaCl), commonly known as “table salt,” is so ubiquitous we rarely pause to consider its fundamental nature. Its humble grains embody a sophisticated dance of electrons and ions — one that has shaped “chemistry, biology, and industry” for centuries.

The ratios known as “parts per million” (ppm) and “parts per billion” (ppb) indicate how many grams of solute there are in one million or one billion grams of sample, respectively. Like percent, these are a measure of concentration. One drop for every million drops, one gram for every million grams, etc. could be considered a “part per million.”

When neutral “sodium” (Na) loses one electron from its outer shell, it forms the “sodium ion” (Na+) (i.e., positively charged sodium atom). "Sodium ion" implies elemental sodium, a monovalent inorganic cation, and “an alkali metal cation”. “Sodium ion” is a monatomic, monocation derived from sodium.