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) There is a dense, positively charged mass in the center of an atom. B) Alpha particles have a positive charge. C) Negative and positive charges are spread evenly throughout 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) concentrated at multiple sites in an atom. D) spread evenly throughout an atom.
A) proton B) electron C) neutron
A) Unlike protons or neutrons, electrons have no mass. B) An electron has far less mass then either a proton or a neutron. C) Protons, neutrons, and electrons all have about the same mass. D) Neutrons have no charge and no mass.
A) the number of neutrons B) the mass of the neutron C) the number of protons D) the charge on the electrons
A) mass number B) isotope C) charge D) atomic number
A) atomic number from mass number B) isotope number from atomic number C) mass number from atomic 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 precise location of electrons in an atom B) the mass of the electrons in the atom C) the most likely locations of electrons in an atom D) the number of electrons in an atom
A) the are extremely nonreactive B) they are located in the left-most column of the periodic table C) they form negative ions D) they are usually gases
A) amount of a substance B) mass of a substance C) electric charge of a substance D) volume of a substance
A) mass number B) atomic mass unit C) isotope number D) atomic number
A) its atomic mass B) the ratio of protons to neutrons in atoms of the element C) how tightly atoms are packed in the element D) the number of valence electrons in atoms of the element
A) They have the same mass number B) they do not have the same number of protons C) their masses are identical D) They are isotopes of oxygen
A) column to column B) group to group C) row to row D) element to element
A) sodium, chromium, copper B) phosphorus, nitrogen, oxygen 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) four B) two C) none D) three
A) increases then decreases B) increases C) decreases D) stays the same
A) carbon-12 atom B) neutron C) proton D) chlorine-35 atom
A) -1 B) +1 C) 0 D) -2
A) 1/18 B) 1/1840 C) 0 D) 1
A) period B) mass C) chemical properties D) number of neutrons
A) losing or gaining protons B) changing from lithium into fluorine C) losing or gaining electrons D) changing from one period to another
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 can form compounds with bright colors B) they are highly reactive C) they are rare in nature D) They exist as single elements rather than molecules
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 left B) on the right C) in the middle D) on the bottom
A) one liter of a pure substance B) one gram of a pure substance C) one mole of a pure substance D) one kilogram of a pure substance.
A) 79 B) 35 C) 80 D) 172
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