A) each element contributes an equal number of atoms. B) their masses are always equal. C) the ratio of their masses is always the same. 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) Gold is not as dense as previously thought. D) Alpha particles have a positive charge.
A) located in the space outside the nucleus. B) spread evenly throughout an atom. C) concentrated at multiple sites in an atom. D) concentrated in the center of an atom.
A) proton B) neutron C) electron
A) Neutrons have no charge and no mass. B) Protons, neutrons, and electrons all have about the same 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 neutrons C) the mass of the neutron D) the number of protons
A) mass number B) atomic number C) isotope D) charge
A) mass number from atomic number B) isotope number from atomic number C) atomic number from mass number D) atomic number from electron number
A) like balls rolling down a hill. B) like beach balls on water waves. C) like planets orbiting the sun. D) like popcorn in a popper.
A) the precise location 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 number 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 number D) atomic mass unit
A) the number of valence electrons in atoms of the element B) its atomic mass C) the ratio of protons to neutrons in atoms of the element D) how tightly atoms are packed in the element
A) they do not have the same number of protons B) They have the same mass number C) They are isotopes of oxygen D) their masses are identical
A) column to column B) row to row C) element to element D) group to group
A) helium, carbon, gold B) sodium, chromium, copper C) iodine, iron, nickel D) phosphorus, nitrogen, oxygen
A) the discovery of elements with predicted properties. B) the discovery of the nucleus. C) the immediate acceptance by other scientists. D) the discovery of subatomic particles.
A) four B) three C) none D) two
A) decreases B) stays the same C) increases then decreases D) increases
A) proton B) neutron C) chlorine-35 atom D) carbon-12 atom
A) 0 B) +1 C) -2 D) -1
A) 0 B) 1/18 C) 1 D) 1/1840
A) period B) chemical properties C) number of neutrons D) mass
A) changing from one period to another B) losing or gaining electrons C) changing from lithium into fluorine D) losing or gaining protons
A) one-fifteenth the mass of a nitrogen-15 atom B) one-twelfth the mass of a carbon-12 atom C) one-half the mass of a hydrogen atom D) one-fourth the mass of a lithium atom
A) they can form compounds with bright colors B) they are rare in nature C) They exist as single elements rather than molecules 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) in the middle C) on the left D) on the right
A) one kilogram of a pure substance. B) one gram of a pure substance C) one mole of a pure substance D) one liter of a pure substance
A) 172 B) 79 C) 80 D) 35
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