A) the ratio of their masses is always the same. B) their masses are always equal. C) their volumes are always equal. D) each element contributes an equal number of atoms.
A) Alpha particles have a positive charge. B) Negative and positive charges are spread evenly throughout an atom. C) There is a dense, positively charged mass in the center of an atom. D) Gold is not as dense as previously thought.
A) concentrated in the center of an atom. B) located in the space outside the nucleus. C) spread evenly throughout an atom. D) concentrated at multiple sites in an atom.
A) neutron B) electron C) proton
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 charge on the electrons B) the number of neutrons C) the mass of the neutron D) the number of protons
A) charge B) isotope C) atomic number 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 balls rolling down a hill. B) like planets orbiting the sun. C) like beach balls on water waves. D) like popcorn in a popper.
A) the most likely locations of electrons in an atom B) the number of electrons in an atom C) the precise location of electrons in an atom D) the mass of the electrons in the atom
A) they form negative ions B) they are usually gases C) the are extremely nonreactive D) they are located in the left-most column of the periodic table
A) mass of a substance B) amount of a substance C) electric charge of a substance D) volume 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) how tightly atoms are packed in the element D) its atomic mass
A) They are isotopes of oxygen B) They have the same mass number C) they do not have the same number of protons D) their masses are identical
A) element to element B) column to column C) row to row D) group to group
A) phosphorus, nitrogen, oxygen B) sodium, chromium, copper C) helium, carbon, gold D) iodine, iron, nickel
A) the discovery of the nucleus. B) the immediate acceptance by other scientists. C) the discovery of subatomic particles. D) the discovery of elements with predicted properties.
A) none B) three C) four D) two
A) increases B) increases then decreases C) decreases D) stays the same
A) chlorine-35 atom B) proton C) neutron D) carbon-12 atom
A) 0 B) -1 C) +1 D) -2
A) 1/1840 B) 1/18 C) 0 D) 1
A) period B) number of neutrons C) mass D) chemical properties
A) changing from one period to another B) losing or gaining protons C) losing or gaining electrons D) changing from lithium into fluorine
A) one-twelfth the mass of a carbon-12 atom B) one-fourth the mass of a lithium atom C) one-fifteenth the mass of a nitrogen-15 atom D) one-half the mass of a hydrogen atom
A) they are rare in nature B) they can form compounds with bright colors C) they are highly reactive D) They exist as single elements rather than molecules
A) have large atomic masses but small atomic numbers B) are extremely hard C) do not form compounds D) can conduct electric current only under certain conditions
A) in the middle B) on the left C) on the bottom D) on the right
A) one mole of a pure substance B) one liter of a pure substance C) one gram of a pure substance D) one kilogram of a pure substance.
A) 79 B) 35 C) 80 D) 172
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