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