Subatomic Particles

Protons (p⁺): Equal to the atomic number (Z). Determines the element.
Neutrons (n⁰): Mass number − atomic number (A − Z).
Electrons (e⁻): For neutral atoms, equals protons. For ions: protons − charge.
Mass number (A): Protons + neutrons.

Isotope Notation

The mass number is written as a superscript and the atomic number as a subscript to the left of the element symbol. Charge appears as a superscript to the right.

Subatomic Particles Practice

Determine the missing value for each atom or ion.

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