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