Science Study Guide

Atoms

Atoms

The building blocks of matter.

Subatomic particles

Protons, Neutrons, Electrons.

Atomic Number

The number of protons in an atom, also the number of electrons.

Atomic Mass

The average mass of all the atoms of an element.

Ion

An atom or molecule with a positive or negative charge.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Isotope

Atoms of the same element with different numbers of neutrons.

Group

Columns on the periodic table, there are 18 groups.

Period

Rows on the periodic table, there are 7 periods.

Metals

Elements that are solid at room temperature.

Metalloids

Elements with properties of both metals and non-metals.

Nonmetals

Elements that are gases at room temperature.

Valence Electrons

Electrons on the outermost shell of an atom.

Octet Rule

Atoms tend to have 8 valence electrons for stability.

Noble Gases

Inert elements with 8 valence electrons.

Ionic Bond

The result of attraction between ions.

Covalent Bond

Atoms share one or more pairs of electrons.

Nonpolar Covalent Bond

Electrons are equally shared between atoms.

Polar Covalent Bond

Electrons are unequally shared between atoms.

Metallic Bond

A force that holds atoms together in a metallic substance.

Hydrogen Bond

Intermolecular force that bonds water molecules together.

Molecule

Formed when two or more atoms are chemically joined.

Compound

Formed when atoms of different elements join chemically.

Chemical Bond

The force of attraction that holds atoms together.

Metal-Metal Bond

Metallic bond between two metal atoms.

Metal-Nonmetal Bond

Ionic bond between a metal and a nonmetal.

Nonmetal-Nonmetal Bond

Covalent bond between two nonmetal atoms.

Lanthanides

Soft metals in the periodic table.

Actinides

Radioactive metals in the periodic table.