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