A) their masses are always equal. B) each element contributes an equal number of atoms. C) the ratio of their masses is always the same. D) their volumes are always equal.
A) Gold is not as dense as previously thought. B) There is a dense, positively charged mass in the center of an atom. C) Alpha particles have a positive charge. D) Negative and positive charges are spread evenly throughout an atom.
A) concentrated in the center of an atom. B) located in the space outside the nucleus. C) spread evenly throughout an atom. D) concentrated at multiple sites in an atom.
A) neutron B) electron C) proton
A) An electron has far less mass then either a proton or a neutron. B) Unlike protons or neutrons, electrons have no mass. C) Neutrons have no charge and no mass. D) Protons, neutrons, and electrons all have about the same mass.
A) the number of protons B) the number of neutrons C) the mass of the neutron D) the charge on the electrons
A) mass number B) isotope C) charge D) atomic number
A) mass number from atomic number B) atomic number from electron number C) atomic number from mass number D) isotope number from atomic number
A) like popcorn in a popper. B) like balls rolling down a hill. C) like beach balls on water waves. D) like planets orbiting the sun.
A) the precise location of electrons in an atom B) the number of electrons in an atom C) the mass of the electrons in the atom D) the most likely locations of electrons in an atom
A) they are usually gases B) they form negative ions C) the are extremely nonreactive D) they are located in the left-most column of the periodic table
A) electric charge of a substance B) volume of a substance C) mass of a substance D) amount of a substance
A) isotope number B) mass number C) atomic mass unit D) atomic number
A) its atomic mass B) how tightly atoms are packed in the element C) the ratio of protons to neutrons in atoms of the element D) the number of valence electrons in atoms of the element
A) they do not have the same number of protons B) They have the same mass number C) their masses are identical D) They are isotopes of oxygen
A) group to group B) row to row C) column to column D) element to element
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 subatomic particles. D) the discovery of elements with predicted properties.
A) two B) three C) four D) none
A) increases then decreases B) decreases C) stays the same D) increases
A) carbon-12 atom B) neutron C) chlorine-35 atom D) proton
A) 0 B) -1 C) +1 D) -2
A) 0 B) 1/1840 C) 1 D) 1/18
A) chemical properties B) mass C) number of neutrons D) period
A) changing from one period to another B) changing from lithium into fluorine C) losing or gaining protons D) losing or gaining electrons
A) one-fifteenth the mass of a nitrogen-15 atom B) one-fourth the mass of a lithium atom C) one-half the mass of a hydrogen 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) have large atomic masses but small atomic numbers B) can conduct electric current only under certain conditions C) do not form compounds D) are extremely hard
A) on the bottom B) on the left C) in the middle D) on the right
A) one liter of a pure substance B) one gram of a pure substance C) one kilogram of a pure substance. D) one mole of a pure substance
A) 35 B) 79 C) 80 D) 172
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