What is Static Electricity?
Static is an electrical imbalance on the surface of a material which can interact with surrounding materials. It is caused by a surplus or deficit of electrons. This surplus or deficit is measured in Coulombs, which are basic units of electrical charge.
A electron has an electric charge of (-) 1.6 x 10-19 Coulombs. A proton has the same charge with a positive polarity. The static charge in Coulombs is directly proportional to the surplus or deficit of electrons i.e. the number of imbalanced ions.
Most people have heard the phrase "Nature abhors a vacuum" a more appropriate statement in terms of electrostatics might be "Atoms want to be stable". A positive ion has a missing electron. So it can easily accept an electron from a negative static charge. A negative ion can be a single electron or an atom/molecule with too many electrons.