Subatomic Particles Practice

The number of protons equals the atomic number (Z), which is unique to each element and found on the periodic table. For example, carbon always has 6 protons.

Neutrons = mass number (A) minus atomic number (Z). The mass number is the total number of protons and neutrons in the nucleus. It is given as a superscript in isotope notation.

For a neutral atom, electrons equal protons (atomic number). For ions, subtract the charge: cations have fewer electrons (Na+ has 10), anions have more electrons (Cl- has 18).

Isotopes are atoms of the same element (same number of protons) with different numbers of neutrons. They have the same chemical properties but different masses. For example, carbon-12 and carbon-14 are isotopes of carbon.