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