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