BIO101 Unit 10
Basic Chemistry
Glossary
atom
smallest unit of an element that displays properties of the element and can combine with other atoms.
atomic number
number of protons found in an atom; elements are arranged on the periodic table by the atomic number from smallest to biggest.
atomic weight
number of protons plus the number of neutrons in the nucleus of an atom; the mass or weight of an atom.
acid
molecules that release hydrogen ions in solution, turns litmus paper pink, a compound of hydrogen and a non-metal, and has a range of 0 to 6.99 on the pH scale.
base
molecules that release OH ions in solution, turns litmus paper blue, a compound of a metal and a OH ion, and has a range of 7.01 to 14 on the pH scale.
buffers
substance that help to resist a change in pH of a solution.
chemical symbol
an abbreviation for an element: Ag – silver, O – oxygen
compound
a substance composed of two or more elements bonded together.
covalent bond
a chemical bond between two atoms that is formed when a pair of electrons are shared by both atoms.
electron
the negatively charged particles of an atom that are found outside the nucleus of an atom in orbits.
element
a substance composed of only one type of atom.
energy
the ability to do work.
gases
a state of matter which does not have a definite shape or volume and fills its’ container.
groups
columns of atoms on the periodic table that have the valence number.
hydrogen bond
a weak bond that forms between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another molecule.
isotope
an atom of an element that differs slightly in weight from other atoms of the same element because there is a difference in the number of neutrons present.
ion
atom with either a positive or negative charge; an atom becomes a positive ion when it gives up an electron and a negative ion when it gains an electron.
ionic bond
a chemical bond that forms between two atoms when electrons are transferred from one atom to the other.
kinetic energy
energy in action.
liquids
a state of matter that has a definite volume but takes the shape of its’ container.
matter
is anything that takes up space and has weight.
molecule
two or more atoms that are held together by a chemical bond.
nucleus
the center of the atom which is usually composed of the atoms protons and neutrons or where the mass of the atom is concentrated.
neutrons
a neutrally charged particle found in the nucleus of an atom.
octet rule
the rule of eights; how atoms interact with each other to have eight electrons in their valence shells.
oxidation
the loss of electrons from an atom or molecule.
periods
the horizontal rows of atoms on the periodic table indicating that they have the same number of shells for their atoms; period 2 atoms have electrons in two shell.
periodic chart or table
a systematic arrangement of the elements by number and periods so that elements with similar properties fall in the same group.
pH scale
a scale from 0 to 14 which is used to indicate the concentration of H or OH ions which indicates whether a solution is an acid or base.
potential energy
stored or inactive energy; energy matter has because of its position or condition.
proton
the positively charged particles that are found in the nucleus of an atom.
reduction
the gain of electrons by an atom or molecule
salt
the product of a reaction between an acid and a base.
shell or orbit
the energy levels around an atom in which electrons orbit.
solids
a state of matter that has a definite shape and volume.
valence number
the number of electrons in the valence shell of an atom.
valence shell
the outermost shell of an atom that contains electrons.