If electrons are gained by atoms of an element does its identity change?

Remember that the number of protons in the nucleus determines an

element's identity. Chemical changes do not affect the nucleus, so

chemical changes cannot change one type of atom into another. The

number of protons in a nucleus does change sometimes, however.

The identity of the atom, therefore, changes.

Recall that the nucleus of an atom contains protons and neutrons.

Attractive forces between these particles hold the nucleus together

even though protons repel one another. When the forces in the nucleus

are strong enough to keep it together, we say the nucleus is stable.

Each element has isotopes with different numbers of neutrons.

The stability of a nucleus depends on the right balance of protons and

neutrons. If there are too few or too many neutrons, the nucleus may

become unstable. When this happens, particles are produced from the

nucleus of the atom. The production of particles restores stability. This

change is accompanied by a release of energy.

The production of particles can change the number of protons.

The atom is thus transformed into an atom of a different element.

In the early 1900s, the physicist Marie Curie named the process by

which atoms produce energy and particles

Isotopes are radioactive if their nuclei have too many or too few

neutrons. Most elements have radioactive isotopes. These isotopes are

rare for small atoms. For the heaviest of elements-those beyond

bismuth (Bi) - all of the isotopes are radioactive. The nucleus gets

too big for the forces to hold it together.

Scientists study radioactivity with a device called a Geiger counter.

The Geiger counter detects the particles and energy from the breakup

of the atomic nucleus. Audible clicks are heard when an atom changes.

More clicks indicate that more particles are being produced.