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