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