Atomic Structure & Periodic Table – Vocabulary Review

Vocabulary flashcards covering atomic structure, periodic trends, bonding, and nanotechnology from the lecture notes.

Period

A horizontal row of elements in the periodic table.

Group

A vertical column of elements in the periodic table that share similar characteristics.

Atomic number

The number of protons in an atom; it determines the element’s identity.

Relative atomic mass

The sum of the number of protons and neutrons in an atom’s nucleus.

Electron shell

A defined area of space around an atom’s nucleus in which electrons move.

Bohr model

A model of the atom that places electrons in discrete shells orbiting the nucleus.

Valence shell

The outermost electron shell of an atom that contains electrons.

Valence electrons

Electrons located in an atom’s valence shell; they largely determine chemical properties.

Electron configuration

A numerical description of how electrons are distributed among an atom’s shells.

Shell diagram

A diagram showing the number of electrons in each electron shell around a nucleus.

Emission spectrum

The unique pattern of coloured lines produced when an element’s electrons release energy as light.

Metals

Elements that are lustrous, malleable, ductile, and good conductors of heat and electricity.

Alkali metal

A highly reactive metal in group 1 of the periodic table with one valence electron.

Alkaline earth metals

Reactive metals found in group 2 of the periodic table with two valence electrons.

Transition metals

Elements in groups 3–12 that often form coloured compounds and can have multiple oxidation states.

Ion

An atom that carries a charge because it has an unequal number of protons and electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic bond

The electrostatic attraction between a positively charged cation and a negatively charged anion.

Ionic compound

A substance composed of cations and anions held together by ionic bonds.

Polyatomic ion

A charged ion consisting of two or more covalently bonded atoms acting as a single unit.

Covalent bond

A bond formed when two or more atoms share pairs of electrons.

Molecule

A group of two or more atoms bonded together, typically by covalent bonds.

Diatomic molecule

A molecule composed of two atoms (e.g., H₂, O₂, N₂).

Delocalised electron

An electron in a metal that is free to move between atoms, contributing to conductivity.

Alloy

A mixture of two or more metals with properties, such as strength, superior to those of pure metals.

Nanotechnology

The manipulation of individual atoms or molecules to form structures at the nanometre scale.

Carbon nanotube

A very small, synthetic tube of carbon atoms notable for strength, lightness, and high conductivity.