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