Ions and pH
Atoms. The atom is made
up of neutrons which have no charge, protons which have a positive
charge, and electrons which have a negative charge. Atoms always
have an equal number of electrons and protons, so the charges
cancel each other out.
Ions. If an atom picks
up an electron (-), it becomes negatively charged; there are
now more electrons than protons. If an atom loses an electron
(-), it becomes positively charged; there are now more protons
than electrons. Atoms with electron imbalances are called ions.
Acids. Acids in water
separate into ions, and the positive ion is hydrogen (H+). When
hydrochloric acid (HCl) mixes with water, it separates into positive
hydrogen (H+) and negative chlorine (Cl-). Hydrogen (H+) combines
with water (H2O) to make hydronium (H3O+).
Bases. Bases in water
also separate into ions, and the negative ion is hydroxide (OH-).
When the base sodium hydroxide (NaOH) mixes with water, it separates
into positive sodium (Na+) and negative hydroxide (OH-).