Physical Science “Properties of Matter” Vocabulary Review

Acid A chemical that produces hydrogen ions when dissolved in water. Click here to reveal the definition!

Atom The smallest particle of an element that has all the element’s chemical properties Click here to reveal the definition!

Atomic Mass The combined number of protons and neutrons in an atom. Click here to reveal the definition!

Atomic Number The number of proton’s in an atom’s nucleus Click here to reveal the definition!

Base A chemical substance that generates hydroxide ions when it dissolves in water. Click here to reveal the definition!

Calorie The scientific unit of heat measurement Click here to reveal the definition!

Compound A chemical substance that is made up of two or more different kinds of atoms that are bonded together. Click here to reveal the definition!

Covalent Bond A bond between elements in which the atoms share electrons. Click here to reveal the definition!

Density The amount of matter in a given volume. D=m/v Click here to reveal the definition!

Electron A negatively charged subatomic particle that moves in an orbit shell outside of an atom’s nucleus. Click here to reveal the definition!

Electron Shell The orbital area outside of an atomic nucleus in which electrons are likely to be found. Click here to reveal the definition!

Element A material that is made up of a single type of atom. Click here to reveal the definition!

Group A vertical column of the periodic table, showing elements with the same number of valence electrons. Click here to reveal the definition!

Half-life The time required for one-half of the atoms of a radioactive substance to decay. Click here to reveal the definition! Simulation of many identical atoms undergoing radioactive decay, starting with either 4 atoms per box (left) or 400 (right). The number at the top is how many half-lives have elapsed. Note the law of large numbers: With more atoms, the overall decay is less random.law of large numbers

Ion An atom that is electrically charged due to loss or gain of one or more electrons. Click here to reveal the definition!

Ionic Bond A bond formed when one atom take electrons and another atom gives up electrons. Click here to reveal the definition! Sodium and fluorine bonding ironically to form sodium fluoride. Sodium loses its outer electron to give it a stable electron configuration, and this electron enters the fluorine atom exothermically. The oppositely charged ions are then attracted to each other, and their bonding releases energy. The net result is that energy leaves the atoms, so the reaction is able to take place.

Isotope An element that can have different mass numbers; isotopes of the same element have the same number of protons but different numbers of neutrons. Click here to reveal the definition!

Joule The unit of measuring work; 1J=1N x 1m Click here to reveal the definition!

Law of Conservation of Matter The scientific law that states that when two objects collide the total momentum of both objects is the same before and after the collision. Click here to reveal the definition!

Mass The amount of matter in something. Click here to reveal the definition!

Mixture A combination of two or more substances held together by physical means, not chemical bonds. Click here to reveal the definition!

Neutron A subatomic particle with no charge, found in the nucleus of an atom. Click here to reveal the definition!

Nuclear Fission A nuclear reaction that splits heavy nucleus into two lighter nuclei. Click here to reveal the definition!

Nuclear Fusion A nuclear reaction that combines two lighter nuclei into one heavier nucleus. Click here to reveal the definition!

Octet Rule In order to become more stable, atoms will take electrons, lose electrons, or share electrons so that their outermost shells are filled with eight electrons. Click here to reveal the definition!

Period A horizontal row in the periodic table. Click here to reveal the definition!

Phase Change A change in the state of matter, such as melting, boiling, or freezing. Click here to reveal the definition!

pH Scale A rating of how acidic or basic a substance is; the scale goes from 0 to 14, with 7 being neutral, values less than 7 being acidic, and values greater than 7 being basic. Click here to reveal the definition!

Product The end result of a chemical reaction. Click here to reveal the definition!

Proton A positively charged particle in the atom’s nucleus. Click here to reveal the definition!

Radioactive Decay The process that occurs when an unstable atom ejects some of its mass as a form of energy in order to become more stable. Click here to reveal the definition!

Reactant An element or compound that combines with other elements or compounds to start a chemical reaction. Click here to reveal the definition!

Valence Electron An electron in an atom’s outer shell. Click here to reveal the definition!

Weight The force with which a body’s mass is pulled towards the center of the Earth. Click here to reveal the definition!