Atoms and ions are the minute and basic particles of all matter. Chemical reactions based upon the composition and interactions of different atoms are responsible for building the parameters of your physical environment.

Atoms are made up of an electron cloud that surrounds a proton and neutron nucleus. Different atoms that have the same number of protons are grouped together as elements. Molecules describe groupings of two or more atoms. Ions are a type of atom or molecule that has lost or gained electrons.

Electrons carry a negative charge, while protons are positively charged. Neutrons do not have any charge. Atoms that have the same number of protons and electrons are not charged. Ions have positive or negative charge because of different numbers of electrons and protons within the atom or molecule.

Neutral atoms are relatively stable because of their lack of charge. Ionization refers to the process of neutral atoms gaining or losing electrons to become ions. Ions are rarely separate from each other; they are attracted to ions of the opposite charge.

Chemical compounds contain at least two separate elements. Chemical compounds sometimes form when oppositely charged ions meet and bond together.

Atoms are held together by nuclear and electromagnetic force. Separate atoms may share electrons to form covalent bonds as molecules. Of course, ionic bonds describe ions that are attracted to each other by opposite charge.