- Compounds are substances in which atoms of two or more elements are chemically combined.
Chemical bonding involves either transferring or sharing electrons in the highest occupied energy levels (shells) of atoms in order to achieve the electronic structure of a noble gas
When atoms form chemical bonds by transferring electrons, they form ions.
- Atoms that lose electrons become positively charged ions
- Atoms that gain electrons become negatively charged ions
Ions have the electronic structure of a noble gas (Group 0). The elements in Group 1 of the periodic table, the alkali metals, all react with non-metal elements to form ionic compounds in which the metal ion has a single positive charge.