A) the ratio of their masses is always the same. B) their volumes are always equal. C) their masses are always equal. D) each element contributes an equal number of atoms.
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 at multiple sites in an atom. B) spread evenly throughout an atom. C) located in the space outside the nucleus. D) concentrated in the center of an atom.
A) neutron B) electron C) proton
A) Unlike protons or neutrons, electrons have no mass. B) Neutrons have no charge and no mass. C) Protons, neutrons, and electrons all have about the same mass. D) An electron has far less mass then either a proton or a neutron.
A) the mass of the neutron B) the number of neutrons C) the number of protons D) the charge on the electrons
A) mass number B) isotope C) charge D) atomic number
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 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 number of electrons in an atom B) the precise location of electrons in an atom C) the mass of the electrons in the atom D) the most likely locations of electrons in an atom
A) the are extremely nonreactive B) they are usually gases C) they form negative ions D) they are located in the left-most column of the periodic table
A) volume of a substance B) amount of a substance C) mass of a substance D) electric charge 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) how tightly atoms are packed in the element D) its atomic mass
A) They have the same mass number B) They are isotopes of oxygen C) their masses are identical D) they do not have the same number of protons
A) column to column B) row to row C) group to group D) element to element
A) helium, carbon, gold B) iodine, iron, nickel C) sodium, chromium, copper D) phosphorus, nitrogen, oxygen
A) the discovery of the nucleus. B) the immediate acceptance by other scientists. C) the discovery of subatomic particles. D) the discovery of elements with predicted properties.
A) four B) none C) three D) two
A) stays the same B) increases then decreases C) increases D) decreases
A) neutron B) proton C) carbon-12 atom D) chlorine-35 atom
A) 0 B) -1 C) +1 D) -2
A) 0 B) 1/18 C) 1/1840 D) 1
A) mass B) chemical properties C) period D) number of neutrons
A) losing or gaining protons B) changing from one period to another C) changing from lithium into fluorine D) losing or gaining electrons
A) one-half the mass of a hydrogen atom B) one-fourth the mass of a lithium atom C) one-fifteenth the mass of a nitrogen-15 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) are extremely hard C) have large atomic masses but small atomic numbers D) do not form compounds
A) on the bottom B) in the middle C) on the right D) on the left
A) one liter of a pure substance B) one kilogram of a pure substance. C) one gram of a pure substance D) one mole of a pure substance
A) 35 B) 79 C) 172 D) 80
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