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