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