A) each element contributes an equal number of atoms. B) the ratio of their masses is always the same. C) their masses are always equal. D) their volumes are always equal.
A) Alpha particles have a positive charge. B) Gold is not as dense as previously thought. C) Negative and positive charges are spread evenly throughout an atom. D) There is a dense, positively charged mass in the center of an atom.
A) concentrated in the center of an atom. B) concentrated at multiple sites in an atom. C) spread evenly throughout an atom. D) located in the space outside the nucleus.
A) proton B) electron C) neutron
A) Neutrons have no charge and no mass. B) Unlike protons or neutrons, electrons have no mass. C) Protons, neutrons, and electrons all have about the same mass. D) An electron has far less mass then either a proton or a neutron.
A) the mass of the neutron B) the number of neutrons C) the number of protons D) the charge on the electrons
A) atomic number B) charge C) isotope D) mass number
A) isotope number from atomic number B) mass number from atomic number C) atomic number from mass number D) atomic number from electron number
A) like popcorn in a popper. B) like beach balls on water waves. C) like planets orbiting the sun. D) like balls rolling down a hill.
A) the number of electrons in an atom B) the most likely locations of electrons in an atom C) the precise location of electrons in an atom D) the mass of the electrons in the atom
A) they are usually gases B) the are extremely nonreactive C) they form negative ions D) they are located in the left-most column of the periodic table
A) mass of a substance B) amount of a substance C) volume of a substance D) electric charge of a substance
A) mass number B) atomic mass unit C) isotope number D) atomic number
A) how tightly atoms are packed in the element B) the number of valence electrons in atoms of the element C) the ratio of protons to neutrons in atoms of the element D) its atomic mass
A) they do not have the same number of protons B) They have the same mass number C) They are isotopes of oxygen D) their masses are identical
A) column to column B) element to element C) row to row D) group to group
A) helium, carbon, gold B) sodium, chromium, copper C) iodine, iron, nickel D) phosphorus, nitrogen, oxygen
A) the discovery of the nucleus. B) the discovery of subatomic particles. C) the immediate acceptance by other scientists. D) the discovery of elements with predicted properties.
A) four B) two C) three D) none
A) increases B) increases then decreases C) decreases D) stays the same
A) proton B) carbon-12 atom C) chlorine-35 atom D) neutron
A) 0 B) -1 C) -2 D) +1
A) 1/1840 B) 1/18 C) 0 D) 1
A) period B) mass C) number of neutrons D) chemical properties
A) changing from one period to another B) changing from lithium into fluorine C) losing or gaining protons D) losing or gaining electrons
A) one-half the mass of a hydrogen atom B) one-twelfth the mass of a carbon-12 atom C) one-fourth the mass of a lithium atom D) one-fifteenth the mass of a nitrogen-15 atom
A) they are rare in nature B) They exist as single elements rather than molecules C) they are highly reactive D) they can form compounds with bright colors
A) have large atomic masses but small atomic numbers B) are extremely hard C) can conduct electric current only under certain conditions D) do not form compounds
A) on the right B) on the left C) in the middle D) on the bottom
A) one gram of a pure substance B) one liter of a pure substance C) one kilogram of a pure substance. D) one mole of a pure substance
A) 172 B) 79 C) 35 D) 80
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