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