Matter refers to anything that takes up space and has mass. Matter can exist as a solid, a liquid, or a gas.
Element is a substance that cannot be broken down into another substance by ordinary chemical means. There are only 92 naturally occurring elements, and each of these differs from the others in its properties.
The atomic theory states that elements consist of tiny particles called atoms. Because each element consists of only one kind of atom, the same name is given to an element and its atoms.
One or two letters that represent the name of an element- e.g., H stands for a hydrogen atom, and Na stands for a sodium atom.
Neutral subatomic particle, located in the nucleus and assigned one atomic mass unit.
Positive subatomic particle located in the nucleus and assigned one atomic mass unit.
Negative subatomic particle moving about in an energy level around the nucleus of an atom.
Center of an atom, in which protons and neutrons are found; membrane-bounded organelle within a eukaryotic cell that contains chromosomes and controls the structure and function of the cell.
Mass of an atom equal to the number of protons plus the number of neutrons within the nucleus.
Number of protons within the nucleus of an atom.
Atom of the same element having the same atomic number but a different mass number due to the number of neutrons.
Concentric energy levels in which electrons orbit.
States that an atom other than hydrogen tends to form bonds until it has eight electrons in its outer shell. An atom that already has eight electrons in its outer shell does not react and is inert.
Outer shell of an atom.
Union of two or more atoms of the same element; also, the smallest part of a compound that retains the properties of the compound.
Substance having two or more different elements united chemically in a fixed ratio.
Chemical bond in which ions are attracted to one another by opposite charges.
Charged particle that carries a negative or positive charge.
Compound produced by a reaction between an acid and a base.
Chemical bond in which atoms share one pair of electrons.
Substance that participates in a reaction.
Substance that forms as a result of a reaction.
Ability of an atom to attract electrons toward itself in a chemical bond.
In chemistry, bond in which the sharing of electrons between atoms is unequal.
hydrogen (H) bond
Weak bond that arises between a slightly positive hydrogen atom of one molecule and a slightly negative atom of another molecule or between parts of the same molecule.
Type of molecule that interacts with water by dissolving in water and/or by forming hydrogen bonds with water molecules.
Type of molecule that does not interact with water because it is nonpolar.
Molecules tending to raise the hydrogen ion concentration in a solution and to lower its pH numerically.
Molecules tending to lower the hydrogen ion concentration in a solution and raise the pH numerically.
A logarithmic measure of the hydrogen ion concentration.
Measurement scale for hydrogen ion concentration.
Substance or group of substances that tends to resist pH changes of a solution, thus stabilizing its relative acidity and basicity.
Hydroxide ion (OH−)
One of two ions that result when a water molecule dissociates. It has gained an electron and therefore bears a negative charge (OH-).