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) There is a dense, positively charged mass in the center of an atom. B) Negative and positive charges are spread evenly throughout an atom. C) Alpha particles have a positive charge. D) Gold is not as dense as previously thought.
A) located in the space outside the nucleus. B) concentrated in the center of an atom. C) spread evenly throughout an atom. D) concentrated at multiple sites in an atom.
A) electron B) neutron C) proton
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 charge on the electrons B) the number of protons C) the mass of the neutron D) the number of neutrons
A) mass number B) isotope C) charge D) atomic number
A) atomic number from electron number B) atomic number from mass number C) isotope number from atomic number D) mass number from atomic number
A) like planets orbiting the sun. B) like popcorn in a popper. C) like balls rolling down a hill. D) like beach balls on water waves.
A) the mass of the electrons in the atom B) the most likely locations of electrons in an atom C) the number of electrons in an atom D) the precise location of electrons in an atom
A) they are located in the left-most column of the periodic table B) they form negative ions C) they are usually gases D) the are extremely nonreactive
A) mass of a substance B) amount of a substance C) volume of a substance D) electric charge of a substance
A) mass number B) atomic mass unit C) isotope number D) atomic number
A) how tightly atoms are packed in the element B) the number of valence electrons in atoms of the element C) the ratio of protons to neutrons 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) 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 the nucleus. B) the immediate acceptance by other scientists. C) the discovery of elements with predicted properties. D) the discovery of subatomic particles.
A) two B) none C) four D) three
A) stays the same B) increases then decreases C) decreases D) increases
A) proton B) carbon-12 atom C) neutron D) chlorine-35 atom
A) 0 B) -1 C) -2 D) +1
A) 0 B) 1 C) 1/1840 D) 1/18
A) number of neutrons B) chemical properties C) period D) mass
A) changing from lithium into fluorine B) losing or gaining electrons C) losing or gaining protons D) changing from one period to another
A) one-half the mass of a hydrogen atom B) one-twelfth the mass of a carbon-12 atom C) one-fourth the mass of a lithium atom D) one-fifteenth the mass of a nitrogen-15 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) have large atomic masses but small atomic numbers B) do not form compounds C) are extremely hard D) can conduct electric current only under certain conditions
A) in the middle B) on the bottom C) on the left D) on the right
A) one liter of a pure substance B) one mole of a pure substance C) one kilogram of a pure substance. D) one gram of a pure substance
A) 35 B) 79 C) 80 D) 172
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