Atomic Structure and Terminology

Vocabulary practice covering the fundamental components of atoms, isotopes, ions, and the formulas used to calculate atomic properties.

Atom

The smallest unit of a chemical element that retains its properties, consisting of a nucleus made of protons and neutrons with electrons around it.

Proton

A particle found in the nucleus with a positive charge of $+1$ that determines the chemical element.

Neutron

A particle found in the nucleus with a neutral charge of $0$; its number varies in isotopes.

Electron

A particle found around the nucleus with a negative charge of $-1$ and a mass that is considered negligible.

Atomic number ($Z$)

The number of protons in the nucleus of an atom, represented by the letter $Z$.

Mass number ($A$)

The sum of protons and neutrons in an atom, calculated using the formula $A = \text{protons} + \text{neutrons}$.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons and mass numbers.

Ion

An atom that has gained or lost electrons and therefore possesses an electric charge.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Chemical element

A set of atoms that all have the same number of protons.

Neutral atom

An atom that has the same number of protons and electrons.

Charge Calculation

The formula used to determine an atom's electric charge: $\text{Charge} = \text{protons} - \text{electrons}$.

Neutron Calculation

The formula used to determine the number of neutrons in an atom: $\text{Neutrons} = \text{mass number} - \text{protons}$.