Introduction to Atomic Theory and Structure

Flashcards covering essential vocabulary and concepts related to atomic theory and structure.

Atom

The fundamental building block of matter, consisting of protons, neutrons, and electrons.

Isotope

Atoms of the same element with the same number of protons but different numbers of neutrons.

Ion

An atom or molecule with a net charge due to the loss or gain of one or more electrons.

Atomic Mass Unit (amu)

A unit of mass used to express atomic and molecular weights, defined as one twelfth of the mass of a carbon-12 atom.

Molar Mass

The mass of one mole of a substance, typically expressed in grams per mole (g/mol).

Periodic Table

A tabular arrangement of the chemical elements, organized by atomic number and properties.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

An uncharged subatomic particle in the nucleus of an atom, contributing to its mass.

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Chemical Symbol

One or two-letter abbreviation representing a chemical element.

Mass Number (A)

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

Atomic Number (Z)

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

Molecule

A group of two or more atoms bonded together.

Natural Abundance

The relative percent of a particular isotope present in a naturally occurring sample of an element.

Avogadro's Number

The number of particles in one mole, approximately 6.022 x 10^23.

Cathode Ray Tube

A device used by J.J. Thomson to discover the electron, demonstrating the existence of cathode rays.

Mass Spectrometry

An analytical technique used to measure the mass-to-charge ratio of ions, helping to determine atomic and molecular weights.

Charge of Electron

The fundamental unit of negative electric charge, approximately -1.602 x 10^-19 coulombs.

Rutherford’s Experiment

An experiment that demonstrated the nuclear structure of the atom, showing that most of the mass is concentrated in a small nucleus.

Thomson's Experiment

An experiment that provided evidence for the existence of electrons and led to the conclusion that atoms have negatively charged components.

Chemical Reaction

A process in which atoms rearrange to form new substances, while atoms themselves are neither created nor destroyed.

Compound

Substances formed when two or more elements combine chemically.