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					Vocabulary Words for Chapter 3.4-4.3

Do not print this to turn in, vocabulary must be turned in with your own hand writing!!!

   A. Atom—the smallest particle of an element that retains all the properties of that element;
      is electrically neutral, spherically shaped, and composed of electrons, protons, and
      neutrons.

   B. Atomic Mass—The weighted average mass of the isotopes of that element

   C. Atomic Mass Unit (AMU)—One-twelfth the mass of a carbon-12 atom. (1 Amu is equal
      to the mass of an electron or proton)

   D. Atomic Number—the total number of protons in an atom

   E. Cathode Ray—Radiation that originates from the cathode and travels to the anode of a
      cathode ray tube

   F. Compound—A chemical combination of two or more different elements; can be broken
      down into simpler substances by chemical means and has properties different from those
      of its component elements

   G. Dalton’s atomic theory—States that matter is composed of extremely small particles
      called atoms; atoms are invisible and indestructible; atoms of a given element are
      identical in size, mass, and chemical properties; atoms of a specific element are different
      from those of another element; different atoms combine in simple whole-number ratios to
      form compounds; in a chemical reaction, atoms are separated, combined or rearranged

   H. Electron—A negatively charged, fast-moving particle with an extremely small mass that
      is found in all forms of matter and moves through the empty space surrounding an atom’s
      nucleus

   I. Element—A pure substance that cannot be broken down into simpler substances by
      physical or chemical means.

   J. Isotope—Atoms of the same element with different numbers of neutrons

   K. Law of definite Proportions—States that, regardless of the amount, a compound Is always
      composed of the same elements in the same proportion by mass (water is made up of
      H20, regardless of if there is 10 grams of water or 100 grams of water).

   L. Law of multiple Proportions—States that when different compounds are formed by the
      combination of the same elements, different masses of one element combine with the
      same mass of the other element in a ration of small whole numbers. (Water is a
      combination of 2 hydrogen and 1 oxygen which is H2O. Peroxide is a combination of 2
      hydrogen and 2 oxygen which is H2O2.)
M. Mass Number—The number after an element’s name, representing the sum of its protons
   and neutrons

N. Neutrons-A neutral, subatomic particle in an atom’s nucleus that has a mass nearly equal
   to that of a proton.

O. Nucleus—The extremely small, positive charged, dense center of an atom that contains
   positively charged protons and neutral neutrons

P. Periodic Table—A chart that organizes all known elements into a grid of horizontal rows
   (periods) and vertical columns (groups or families) arranged by increasing atomic
   number

Q. Percent by mass-A percentage determined by the ratio of the mass of each element to the
   total mass of the compound

R. Protons-A subatomic particle in an atom’s nucleus that has a positive charge of 1+

				
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