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