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