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