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