When atoms are chemically bonded to atoms of the same type, the bonding electrons are shared. Both of the atom in a bond own the same number of electrons as an isolated atom of that type.
In some compounds atoms of different elements bonded to one another are charged. This is because each of the bonded atoms own a different number of electrons than they did as an isolated atom.
These compounds are referred to as ionic. The charged atoms or groups of atoms are referred to as ions.
Salt shaker Wikipedia Dubravko SorićNaCl (table salt) is an ionic compound which exists as Na+ and Cl– ions.
Ions are atoms or groups of atoms that bear an electrical charge because the number of electrons differs from the number of protons.
Positive ions are known as cations and have fewer electrons than protons.
Li atoms (atomic number 3) have 3 protons and 3 electrons. Li+ ions have 3 protons and 2 electrons.
Negative ions are known as anions and have more electrons than protons.
I (iodine) atoms (atomic number 53) have 53 protons and 53 electrons. I– (iodide) ions have 53 protons and 54 electrons.
The composition of the nucleus for both cations and anions is the same as the coresponding atom. Thus the number of protons and neutrons is the same.
