Atoms and Elements Vocabulary

A comprehensive set of vocabulary flashcards covering key concepts related to atoms and elements essential for understanding chemistry.

Atom

The smallest unit of matter that retains the properties of an element.

Electron

A negatively charged subatomic particle found outside the nucleus of an atom.

Element

A pure substance made of only one type of atom.

Atomic Number

The number of protons in the nucleus of an atom.

Molecule

A group of two or more atoms that are chemically bonded together.

Compound

A substance made of two or more different elements that are chemically bonded together in a fixed ratio.

Subscript

A small number written at the lower right of a chemical symbol in a formula, indicating how many atoms of that element are in a molecule.

Proton

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

Atomic Mass

The total mass of an atom, mostly determined by the number of protons and neutrons in its nucleus.

Periodic Table

An organized chart of all known elements, arranged based on their atomic number and grouped by similar chemical properties.

Ion

An atom or molecule that has gained or lost one or more electrons, giving it a positive or negative charge.

Chemical Symbol

A one- or two-letter abbreviation that represents a chemical element.

Groups

The vertical columns of elements in the Periodic Table; elements in the same group have similar chemical properties.

Neutron

A subatomic particle found in the nucleus of an atom, which has no electrical charge (neutral) and adds mass to the atom.

Chemical Formula

A way of using symbols and numbers to show the types and numbers of atoms in a substance.

Coefficient

A number placed in front of a chemical formula in a chemical equation that tells how many molecules or atoms of that substance are involved in the reaction.

Lewis Structure

A diagram that shows the valence electrons of atoms in a molecule using dots to represent electrons and lines for bonds.

Ball & Stick Model

A 3D representation of a molecule showing atoms as balls and bonds as sticks connecting them.

Period

A horizontal row of elements in the Periodic Table, where properties change gradually across the row.

Chemical Equation

A written representation of a chemical reaction, showing the reactants and products.