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