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