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