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