Atoms, Molecules, and Ions

A series of vocabulary flashcards covering key concepts from the Chemistry lecture on atoms, molecules, and ions.

Proton

A subatomic particle with a positive charge found in the nucleus of an atom.

Neutron

A subatomic particle with no charge, found in the nucleus of an atom.

Electron

A subatomic particle with a negative charge that orbits the nucleus of an atom.

Atomic Number

The number of protons in the nucleus of an atom, which determines the identity of the element.

Mass Number

The total number of protons and neutrons in the nucleus of an atom.

Isotope

Atoms of the same element that have different numbers of neutrons and different masses.

Atomic Mass Unit (amu)

A unit of mass used to express atomic and molecular weights, based on the mass of hydrogen.

Atomic Weight

The average mass of an element's isotopes, weighted by their relative abundances.

Periodic Table

A systematic organization of elements arranged by increasing atomic number.

Molecule

A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound.

Ionic Compound

A compound formed from the electrostatic attraction between oppositely charged ions. Generally formed between metals and non metals.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Chemical Nomenclature

The system of naming compounds based on their composition and structure.

Empirical Formula

A formula that gives the simplest whole-number ratio of atoms of each element in a compound.

Molecular Formula

A formula that shows the exact number of atoms of each element in a molecule.

Diatomic Molecule

A molecule composed of two atoms of the same or different elements.

Metalloids

Elements that exhibit properties of both metals and nonmetals.