A) their masses are always equal. B) each element contributes an equal number of atoms. C) their volumes are always equal. D) the ratio of their masses is always the same.
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) located in the space outside the nucleus. B) concentrated in the center of an atom. C) concentrated at multiple sites in 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 mass of the neutron B) the number of protons C) the number of neutrons D) the charge on the electrons
A) charge B) mass number C) atomic number D) isotope
A) atomic number from electron number B) atomic number from mass number C) mass number from atomic number D) isotope number from atomic 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 number of electrons in an atom B) the mass of the electrons in the atom C) the most likely locations 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) electric charge of a substance B) mass of a substance C) amount of a substance D) volume of a substance
A) atomic number B) atomic mass unit C) isotope number D) mass number
A) the number of valence electrons in atoms of the element B) its atomic mass C) how tightly atoms are packed in the element D) the ratio of protons to neutrons in atoms of the element
A) They have the same mass number B) their masses are identical C) they do not have the same number of protons D) They are isotopes of oxygen
A) column to column B) row to row C) element to element D) group to group
A) phosphorus, nitrogen, oxygen B) sodium, chromium, copper C) helium, carbon, gold D) iodine, iron, nickel
A) the discovery of elements with predicted properties. B) the discovery of subatomic particles. C) the discovery of the nucleus. D) the immediate acceptance by other scientists.
A) three B) four C) none D) two
A) decreases B) increases C) increases then decreases D) stays the same
A) proton B) carbon-12 atom C) chlorine-35 atom D) neutron
A) 0 B) +1 C) -1 D) -2
A) 1/18 B) 1/1840 C) 1 D) 0
A) period B) chemical properties C) mass D) number of neutrons
A) losing or gaining electrons B) losing or gaining protons C) changing from lithium into fluorine D) changing from one period to another
A) one-fourth the mass of a lithium atom B) one-half the mass of a hydrogen 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 are highly reactive C) they are rare in nature D) they can form compounds with bright colors
A) can conduct electric current only under certain conditions B) do not form compounds C) are extremely hard D) have large atomic masses but small atomic numbers
A) on the left B) on the right C) in the middle D) on the bottom
A) one kilogram of a pure substance. B) one mole of a pure substance C) one gram of a pure substance D) one liter of a pure substance
A) 172 B) 79 C) 80 D) 35
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