The smallest unit of matter that retains the properties of an element.
An atom that has gained or lost one or more electrons, thus acquiring a charge.
Substances made from one type of atom only.
A substance containing two or more elements in a fixed ratio.
Ionic compound. A compound resulting from the formation of ionic bonds.
The number of protons in an atom of an element.
The number of protons plus neutrons.
The average atomic mass for all the isotopes of that element.
A variant of an atom, with a different number of neutrons.
An isotope with a large and unstable nucleus that decays spontaneously, giving off particles and energy.
An energy level representing the distance of an electron from the nucleus of an atom. Orbital layer.
A subatomic particle, with a single negative charge, that moves around the nucleus of an atom.
A subatomic particle, with a single positive charge, found in the nucleus of an atom.
A subatomic particle, with no electrical charge, found in the nucleus of an atom. Neutrons glue the protons together so that they are not repelled by each other's positive charge.
An attraction between two atoms resulting from a sharing of valence electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.
A chemical bond resulting from the attraction between oppositely charged ions.
An attraction between atoms that share one or more pairs of valence electrons.
polar covalent bond
A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
nonpolar covalent bond
A covalent bond in which electrons are shared equally between two atoms of similar electronegativity.
A group of two or more atoms held together by chemical bonds.
The attraction of a given atom for the electrons of a covalent bond.
A molecule containing polar covalent bonds.
A weak chemical bond formed when the partially positive hydrogen atom participating in a polar covalent bond is attracted to the partially negative atom participating in another polar covalent bond.
A substance that is dissolved in a solution.
The dissolving agent of a solution.
A liquid consisting of a solute dissolved into a solvent.
A starting material in a chemical reaction.
An ending material in a chemical reaction.
The making and breaking of chemical bonds, leading to changes in the composition of matter.
The binding together of like molecules, often by hydrogen bonds.
A measure of how difficult it is to stretch or break the surface of a liquid because of the hydrogen bonding of surface molecules.