When the numbers of protons and electrons in an atom are equal, scientists say the atom is balanced. It is possible, however, to unbalance an atom by brushing away one or more electrons.

Unbalanced atoms occur when materials rub together, as when people slide across the plastic seat of an automobile or walk across a wool rug. Because of the rubbing, electrons are brushed away from some atoms.

When atoms are unbalanced, there is a tendency for electrons to move until the atom's balance is regained.

The shock you may have felt when you touched a door handle was caused by such a movement of electrons.

Look at this picture of a carbon atom: This atom is balanced and has six protons and six electrons. Electrons and protons in all atoms are electrically charged -- electrons are negatively charged; protons are positively charged.

If one electron in the drawing is brushed away, there will be more positive charges than negative charges. Because of this, this unbalanced atom will be said to have a positive
charge.

If the carbon atom had gained an electron instead of losing one, it would have more negative charges than positive ones.

When an extra electron is picked up by an atom, it becomes negatively unbalanced and is said to have a negative charge.

When an atom gains or loses electrons, does that change the atom into something else? Can a certain kind of atom be the same kind of atom if it has more or less electrons than usual? If a hydrogen atom has a certain number of electrons and protons, and it loses some, is it still a hydrogen atom?