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