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