Atoms & The Periodic Table

Vocabulary flashcards covering the components of atomic structure, historical atomic models, subatomic particle properties, ions, and the Periodic Table.

Atom

The smallest unit of an element that makes up everything.

Subatomic particles

The smaller particles—specifically protons, neutrons, and electrons—that make up an atom.

Dalton's Atomic Theory (1803)

The theory proposing that all matter is composed of tiny, solid, indivisible atoms, with different elements possessing different types of atoms.

Thomson's Plum Pudding Model (1904)

An atomic model proposed following the discovery of electrons in $1897$, establishing that atoms are composed of smaller particles and are not indivisible.

Rutherford Model (1911)

An atomic model describing a small, dense, positively charged nucleus at the centre of the atom, demonstrating that most of an atom is empty space.

Bohr Model (1913)

An atomic model suggesting that electrons travel around the nucleus in fixed energy levels or shells.

Proton

A positively charged subatomic particle with a charge of $+1$ and a mass of $1\text{ AMU}$, located in the nucleus.

Neutron

A neutrally charged subatomic particle with a charge of $0$ and a mass of $1\text{ AMU}$, located in the nucleus.

Electron

A negatively charged subatomic particle with a charge of $-1$ and a mass of $\frac{1}{1800}\text{ AMU}$, located outside the nucleus in shells.

Nucleus

The small, dense, positively charged centre of an atom where protons and neutrons reside.

Electron Cloud

The region or space outside the nucleus where electrons are likely to be found.

Neutral Atom

An atom that carries no overall charge because the number of protons equals the number of electrons.

Ion

An atom that has lost or gained electrons, causing the charges to no longer balance so that the number of protons does not equal the number of electrons.

Atomic Number

The number of protons located in the nucleus of an atom, which dictates the type of element.

Periodic Table

A reference table that arranges the chemical elements in order of increasing atomic numbers.