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