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