Year 9 Chemistry - Living in a Material World Vocabulary

Flashcards covering core terminology and concepts for Year 9 Chemistry, including atomic structure, chemical bonding types, periodic table organization, alloys, and polyatomic ions.

Atom

The smallest particle of an element that retains the properties of that element.

Element

A pure substance containing only one type of atom.

Molecule

Two or more atoms chemically bonded together.

Compound

A substance containing atoms of two or more different elements chemically bonded together.

Groups

The vertical columns of the Periodic Table, numbered 1 through 18.

Periods

The horizontal rows of the Periodic Table, numbered 1 through 7.

Valence Electrons

The electrons located in the outermost occupied shell of an atom, which are involved in chemical bonding.

Valency

The number of electrons an atom needs to gain, lose, or share to achieve a stable electron configuration.

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 oppositely charged positive and negative ions.

Ionic Lattice

A repeating three-dimensional arrangement of positive and negative ions held together by electrostatic attraction.

Lewis Electron-Dot Diagram

A diagram that uses dots surrounding an element symbol to represent its valence electrons.

Lone Pair

A pair of valence electrons that is not shared in a covalent bond.

Covalent Bond

A chemical bond formed when two non-metal atoms share a pair of electrons.

Double Covalent Bond

A covalent bond containing two shared pairs of electrons ($4$ shared electrons), represented by two bond lines.

Triple Covalent Bond

A covalent bond containing three shared pairs of electrons ($6$ shared electrons), represented by three bond lines.

Diatomic Molecule

A molecule that contains two covalently bonded atoms, such as $H_2$, $N_2$, $O_2$, $F_2$, $Cl_2$, $Br_2$, and $I_2$.

Covalent Network

A very large structure in which atoms are connected by covalent bonds continuously throughout the entire structure.

Delocalised Electrons

Electrons that are not associated with any single atom or ion and can move freely throughout a structure.

Metallic Bonding

The electrostatic attraction between positive metal ions and delocalised electrons throughout a metal structure.

Malleability

The ability of a material to be hammered, pressed, or rolled into different shapes without breaking.

Ductility

The ability of a material to be drawn or stretched into a thin wire.

Electrical Conductivity

The ability of a material to allow electrical charge or electric current to pass through it.

State Symbol $(aq)$

A notation denoting an aqueous substance, meaning it is dissolved in water.

Alloy

A material containing a metal combined with one or more other elements.

Substitutional Alloy

An alloy in which atoms of another element replace some of the atoms of the original base metal in the structure.

Interstitial Alloy

An alloy in which smaller atoms fit into the spaces between the larger atoms of the base metal.

Polyatomic Ion

A group of two or more covalently bonded atoms that together carry an overall electrical charge.