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