Atoms and Periodic Table - Vocabulary Flashcards

Vocabulary flashcards covering key terms from the notes on atoms and the periodic table.

Atom

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

Proton

A positively charged subatomic particle located in the nucleus.

Neutron

A neutrally charged subatomic particle located in the nucleus.

Electron

A negatively charged subatomic particle located outside the nucleus.

Atomic number

The number of protons in the nucleus of an atom.

Average atomic mass

The weighted average mass of the naturally occurring isotopes of an element.

Mass number

The sum of the number of protons and neutrons in an atomic nucleus.

Ion

An atom or group of atoms that has a positive or negative charge.

Isotope

Atoms of the same element that have different numbers of neutrons.

Periodic table

A chart of the elements showing the repeating pattern of their properties.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Valence electrons

Electrons on the outermost energy level of an atom.

Lewis Dot Structure

A diagram of a molecule using dots to represent valence electrons.

Alkali metals

Group 1 metals with 1 valence electron; very reactive; soft; silver; shiny; low density (examples: Li, Na, K, Rb, Cs, Fr).

Alkaline earth metals

Group 2 metals that are harder than alkali metals and less reactive.

Halogens

Group of nonmetals with 7 valence electrons; highly reactive.

Noble gases

Group 18 elements that are nonreactive (inert) under standard conditions.

Metals

Elements that are good conductors of heat and electricity.

Nonmetals

Elements that are poor conductors of heat and electricity.

Metalloids

Elements with properties intermediate between metals and nonmetals.