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