Neutral: definition in chemistry
Neutral: Having no overall electric charge, or, for a solution, being neither acidic nor basic (pH 7 at 25 °C).
An atom is electrically neutral when it has the same number of electrons as protons, so their charges cancel. Ionic compounds are neutral overall because the charges of their ions balance, which is how you work out formulas such as CaCl₂. A neutral solution has equal concentrations of hydrogen ions and hydroxide ions, and an acid and a base neutralize each other to form water and a salt.
Examples
- A sodium atom (11 protons, 11 electrons) is neutral
- Pure water at 25 °C has a pH of 7
- In CaCl₂, one Ca²⁺ ion balances two Cl⁻ ions
- The neutron is a subatomic particle with no charge
On the periodic table
Each element on the table is shown as a neutral atom, so its atomic number gives both its number of protons and its number of electrons.