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