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