A) each element contributes an equal number of atoms. B) the ratio of their masses is always the same. C) their masses are always equal. D) their volumes are always equal.
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) concentrated at multiple sites in an atom. B) concentrated in the center of an atom. C) located in the space outside the nucleus. D) spread evenly throughout an atom.
A) proton B) neutron C) electron
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 mass of the neutron B) the number of neutrons C) the charge on the electrons D) the number of protons
A) atomic number B) isotope C) charge D) mass number
A) atomic number from electron number B) mass number from atomic number C) isotope number from atomic number D) atomic number from mass number
A) like popcorn in a popper. B) like beach balls on water waves. C) like balls rolling down a hill. D) like planets orbiting the sun.
A) the number of electrons in an atom B) the precise location of electrons in an atom C) the most likely locations of electrons in an atom D) the mass of the electrons in the atom
A) they are usually gases B) the are extremely nonreactive C) they form negative ions D) they are located in the left-most column of the periodic table
A) mass of a substance B) volume of a substance C) amount of a substance D) electric charge of a substance
A) mass number B) atomic number C) isotope number D) atomic mass unit
A) the ratio of protons to neutrons in atoms of the element B) its atomic mass C) the number of valence electrons in atoms of the element D) how tightly atoms are packed in the element
A) They have the same mass number B) They are isotopes of oxygen C) their masses are identical D) they do not have the same number of protons
A) column to column B) element to element C) row to row D) group to group
A) helium, carbon, gold B) sodium, chromium, copper C) phosphorus, nitrogen, oxygen D) iodine, iron, nickel
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) none B) two C) three D) four
A) increases B) stays the same C) increases then decreases D) decreases
A) proton B) carbon-12 atom C) chlorine-35 atom D) neutron
A) -2 B) +1 C) -1 D) 0
A) 1 B) 0 C) 1/18 D) 1/1840
A) chemical properties B) period C) number of neutrons D) mass
A) losing or gaining electrons B) losing or gaining protons C) changing from one period to another D) changing from lithium into fluorine
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 are highly reactive C) they can form compounds with bright colors D) they are rare in nature
A) can conduct electric current only under certain conditions B) do not form compounds C) have large atomic masses but small atomic numbers D) are extremely hard
A) on the right B) in the middle C) on the left D) on the bottom
A) one liter of a pure substance B) one mole of a pure substance C) one gram of a pure substance D) one kilogram of a pure substance.
A) 80 B) 172 C) 35 D) 79
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