PS.4 Periodic Table Vocabulary

A pure substance composed of the same type of atom throughout

• compound
• mixture
• solution
• element

The number of protons in the nucleus of one atom of an element

• Atomic number
• Mass number
• Neutron number
• Electron number

The weighted average mass of an element based on the abundances of the naturally occurring isotopes of that element

• isotopic mass
• atomic weight
• molar mass
• atomic mass

A one- or two-letter representation of a specific element, sometimes referred to as an atomic symbol

• Chemical formula

• Chemical symbol
• Group

The rows in a periodic table that classify the elements by the number of electron shells

• groups
• valence electrons
• periods
• atomic numbers

The columns on a periodic table that arrange the elements by the number of electrons that are in the outermost shell; also called families

• periods
• blocks
• valence shells
• groups

Elements that are typically solid, shiny, malleable, and good conductors of heat and electricity; includes most elements

• metals
• metalloids

• nonmetals
• gases

Elements that are typically not shiny, not malleable, and poor conductors of heat and electricity; usually gases or brittle solids

• nonmetals
• alkali metals
• metals
• metalloids

Elements that have properties of both metals and nonmetals; sometimes referred to as semiconductors

• metalloids
• conductors
• nonmetals
• metals

A shorthand notation that uses chemical symbols and numbers as subscripts to represent the type and number of atoms that are present in the smallest unit of a substance

• elemental representation
• chemical formula
• molecular formula
• atomic notation