A) each element contributes an equal number of atoms. B) their volumes are always equal. C) the ratio of their masses is always the same. D) their masses are always equal.
A) Alpha particles have a positive charge. B) Negative and positive charges are spread evenly throughout an atom. C) Gold is not as dense as previously thought. D) There is a dense, positively charged mass in the center of an atom.
A) concentrated at multiple sites in an atom. B) spread evenly throughout an atom. C) concentrated in the center of an atom. D) located in the space outside the nucleus.
A) proton B) electron C) neutron
A) Unlike protons or neutrons, electrons have no mass. B) Neutrons have no charge and no mass. C) Protons, neutrons, and electrons all have about the same 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 charge on the electrons D) the mass of the neutron
A) isotope B) atomic number C) charge 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 popcorn in a popper. C) like beach balls on water waves. D) like planets orbiting the sun.
A) the most likely locations of electrons in an atom B) the precise location of electrons in an atom C) the number of electrons in an atom D) the mass of the electrons in the atom
A) the are extremely nonreactive B) they are usually gases C) they are located in the left-most column of the periodic table D) they form negative ions
A) volume of a substance B) amount of a substance C) electric charge of a substance D) mass of a substance
A) atomic mass unit B) isotope number C) mass number D) atomic number
A) how tightly atoms are packed in the element B) its atomic mass C) the number of valence electrons in atoms of the element D) the ratio of protons to neutrons 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) group to group B) element to element C) row to row D) column to column
A) phosphorus, nitrogen, oxygen B) helium, carbon, gold C) iodine, iron, nickel D) sodium, chromium, copper
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) four C) three D) none
A) stays the same B) increases C) decreases D) increases then decreases
A) carbon-12 atom B) neutron C) proton D) chlorine-35 atom
A) -2 B) +1 C) 0 D) -1
A) 1/18 B) 1 C) 0 D) 1/1840
A) chemical properties B) mass C) period D) number of neutrons
A) losing or gaining protons B) changing from lithium into fluorine C) changing from one period to another D) losing or gaining electrons
A) one-half the mass of a hydrogen atom B) one-fourth the mass of a lithium atom C) one-fifteenth the mass of a nitrogen-15 atom D) one-twelfth the mass of a carbon-12 atom
A) They exist as single elements rather than molecules B) they can form compounds with bright colors C) they are rare in nature D) they are highly reactive
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 gram of a pure substance B) one kilogram of a pure substance. C) one liter of a pure substance D) one mole of a pure substance
A) 35 B) 172 C) 79 D) 80
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