Atoms and the Periodic Table Practice Flashcards

A set of vocabulary flashcards covering the basics of atomic structure, historical atomic models, electron configuration, and the organization of the periodic table.

Atom

Derived from the Greek word Atomos, meaning indivisible; it represents the basic unit of matter.

Nucleus

A dense cluster at the center of an atom consisting of two types of particles: protons and neutrons.

Protons

Positively charged subatomic particles located in the nucleus that determine the type of element through the atomic number.

Neutrons

Subatomic particles with no charge that, when combined with protons, determine the atomic mass of an element.

Electrons

Negatively charged subatomic particles that move around the nucleus in a cloud and are approximately $1800$ times smaller than protons or neutrons.

Atomic Number

The number of protons in an atom, which in a neutral state is equal to the number of electrons.

Mass Number

The total number of particles in the nucleus of an atom, calculated as the sum of the number of protons and the number of neutrons.

Electrostatic attraction

The force that holds an atom together by attracting negatively charged electrons to the positively charged nucleus.

James Chadwick

A British physicist who confirmed the existence of neutrons in $1932$.

Electron Shells

Energy levels or spherical shells around the nucleus where electrons are arranged; the first three shells can typically hold $2$, $8$, and $18$ electrons respectively.

Ion

An atom that has lost or gained electrons, resulting in a net electrical charge rather than being neutral.

Anion

A negatively charged ion formed when an atom gains electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Valency

Also known as electrovalency, this is the overall charge of an atom found by subtracting the number of electrons from the number of protons.

Valence Electrons

The electrons located in the outermost shell (valence shell) of an atom.

Periods

The horizontal rows in the periodic table, labelled $1$ through $7$, which indicate the number of electron shells an element has.

Groups

The vertical columns in the periodic table, labelled $1$ through $18$, containing elements with similar physical properties.

Alkali Metals

Group $1$ elements that are very soft and highly reactive with water and oxygen.

Halogens

Group $17$ elements that are characterized by being coloured and highly reactive.

Noble Gases

Group $18$ elements that are very stable, unreactive, and monoatomic because they already have full outer shells.

Metalloids

A group of seven elements that separate metals and non-metals and possess properties of both types.

Malleable

A property of most metals describing their ability to be hammered or pressed into shape without breaking.

Ductile

A property of most metals describing their ability to be drawn out into thin wires.

Ground State

The condition where all electrons in an atom are occupying their lowest possible energy levels.

Excited State

A state where valence electrons jump to a higher energy level after absorbing energy, such as heat from a Bunsen burner.