and Answers
elements - ✅✅substance composed of only one type of atom that cannot be broken into simpler
constituents by chemical means
compounds - ✅✅chemical combination of two or more elements
atoms - ✅✅smallest particle of a chemical element that retains the properties of that element;
particles that combine to form molecules
subatomic particles - ✅✅particles that make up atoms; neutrons, protons, electrons
nucleus - ✅✅dense, central core of an atom
protons - ✅✅positively charged subatomic particle
neutrons - ✅✅neutral subatomic particle
electrons - ✅✅small, negatively charged subatomic particle
atomic number - ✅✅number of protons in an atom of an element
mass number (atomic mass) - ✅✅number of protons plus the number of neutrons in an atom of an
element
energy level - ✅✅limited region surrounding the nucleus of an atom at a certain distance containing
electrons; shell
, octet rule - ✅✅atoms with fewer or more than eight electrons in the outer energy level will attempt
to lose, gain, or share electrons with other atoms to achieve stability
inert - ✅✅stable element; maximum amount of electrons in outer shell
atomic weight - ✅✅average atomic mass of an atom of an element as it is found in nature; atomic
weights are usually found in the periodic table of elements
radioisotope - ✅✅unstable isotope that undergoes nuclear breakdown and emits nuclear particles
and radiation
decay - ✅✅emition of nuclear particles and radiation
chemical reaction - ✅✅interaction between two or more atoms that occurs as a result of activity
between electrons in their outermost energy levels
molecules - ✅✅two or more atoms covalently joined together
chemical bonds - ✅✅energy relationship joining two or more atoms; involves sharing or exchange of
electrons
ions - ✅✅electrically charged atom or group of atoms
ionic bond (electrovalent bond) - ✅✅formed by transfer of electrons; strong electrostatic force that
binds positively and negatively charged ions together
covalent bond - ✅✅formed by sharing of electron pairs between atoms
single covalent bond - ✅✅covalent bond with only one pair of shared electrons