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