A) each element contributes an equal number of atoms. B) the ratio of their masses is always the same. C) their masses are always equal. D) their volumes are always equal.
A) Alpha particles have a positive charge. B) Negative and positive charges are spread evenly throughout an atom. C) Gold is not as dense as previously thought. D) There is a dense, positively charged mass in the center of an atom.
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) 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 number of neutrons B) the number of protons C) the charge on the electrons D) the mass of the neutron
A) mass number B) isotope C) atomic number D) charge
A) isotope number from atomic number B) mass number from atomic number C) atomic number from mass number D) atomic number from electron number
A) like planets orbiting the sun. B) like balls rolling down a hill. C) like beach balls on water waves. D) like popcorn in a popper.
A) the precise location of electrons in an atom B) the most likely locations of electrons in an atom C) the mass of the electrons in the atom D) the number of electrons in an atom
A) they are located in the left-most column of the periodic table B) they are usually gases C) the are extremely nonreactive D) they form negative ions
A) amount of a substance B) mass of a substance C) electric charge of a substance D) volume 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) the ratio of protons to neutrons in atoms of the element D) how tightly atoms are packed in the element
A) They are isotopes of oxygen B) their masses are identical C) they do not have the same number of protons D) They have the same mass number
A) row to row B) group to group C) column to column D) element to element
A) iodine, iron, nickel B) phosphorus, nitrogen, oxygen C) sodium, chromium, copper D) helium, carbon, gold
A) the discovery of subatomic particles. B) the discovery of elements with predicted properties. C) the immediate acceptance by other scientists. D) the discovery of the nucleus.
A) none B) two C) four D) three
A) stays the same B) increases then decreases C) increases D) decreases
A) carbon-12 atom B) neutron C) chlorine-35 atom D) proton
A) +1 B) 0 C) -1 D) -2
A) 1 B) 1/1840 C) 0 D) 1/18
A) mass B) chemical properties C) number of neutrons D) period
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-fifteenth the mass of a nitrogen-15 atom B) one-half the mass of a hydrogen atom C) one-fourth the mass of a lithium atom D) one-twelfth the mass of a carbon-12 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) do not form compounds B) have large atomic masses but small atomic numbers C) can conduct electric current only under certain conditions D) are extremely hard
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 kilogram of a pure substance. C) one liter of a pure substance D) one mole of a pure substance
A) 172 B) 35 C) 79 D) 80
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