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