Play Science Chemistry Vocabulary

Atoms

the smallest unit of an element

Elements

an atom with a specific number of protons

Molecules

two or more atoms bonded together

Chemical Formula

the symbol that stands for an element

Chemical Reaction

new material formed by the rearrangement of atoms

Balanced Chemical Equation

a chemical equation where both the reactants and the products contain the same amount of atoms for each element

Electrostatic Force

the force of opposite charges that attract one another

Atomic Number

the number of protons in an atom

Mass Number

the combined number of protons and neutrons in an atom

Atomic Weight

the average mass number of all isotopes of an element

Protons

positively charged part of an atom

Neutrons

part of an atom with no charge

Electrons

negatively charged part of an atom

Nucleus

the center of an atom, contains the protons and neutrons

Isotopes

two or more atoms whose nuclei contain the same amount of protons, but different numbers of neutrons

Ions

an atom or group of atoms with a positive or negative charge

Valence Electrons

electrons that lie on the outer shell (orbital) of an atom.

Anions

atoms that tend to lose electrons (negative charge)

Cations

atoms that tend to gain electrons (positive charge)

Positive Valence

atoms that lose electrons

Negative Valence

atoms that gain electrons

Polyatomic Ions

a group of atoms bonded together that have a net positive or negative charge

Mole

6.022 * 10^23 (602,200,000,000,000,000,000,000); the number of atoms in a certain amount of each atom or molecule This amount (in grams) is equal to the atomic weight or formula mass or an atom or molecule

Molar Mass

same as formula mass, unit in grams

Formula Mass

the combined atomic weights of all atoms in a molecule

measures the level of acid in a substance

Sodium Azide Reaction

2 NaN3 --> 3 N2 + 2 Na

Ionic Bonds

the bond between two or more ions that are of opposite charge

Dissociation

ionic compounds splits or breaks apart