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