The Periodic Table: Organization and Element Categories

Vocabulary flashcards covering the components of a periodic table entry, table layout terminology, and the three main element categories.

Atomic number

The number of protons contained in the atomic nucleus of an element.

Relative atomic mass

The average mass of an element's isotopes based on the natural abundance of each isotope, expressed in atomic mass units ($\text{u}$).

Chemical symbol

A one- or two-letter abbreviation designating a specific chemical element in a periodic table cell (such as C for carbon).

Period

A horizontal row of elements in the periodic table.

Family (Group)

A vertical column of elements in the periodic table whose elements share similar physical and chemical properties.

Staircase line (Escalier)

The stepped dividing line on the periodic table that separates metals from non-metals and along which metalloids are located.

Metals

The category of elements situated to the left of the staircase line on the periodic table.

Metalloids

The category of elements bordering the staircase line that exhibit intermediate properties between metals and non-metals, often acting as semiconductors.

Non-metals

The category of elements located to the right of the staircase line (plus hydrogen) that typically behave as insulators.