A) the ratio of their masses is always the same. B) their masses are always equal. C) each element contributes an equal number of atoms. D) their volumes 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) concentrated at multiple sites in an atom. C) concentrated in the center of an atom. D) located in the space outside the nucleus.
A) proton B) neutron 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 number of neutrons B) the mass of the neutron C) the charge on the electrons D) the number of protons
A) atomic number B) charge C) mass number D) isotope
A) atomic number from mass number B) isotope number from atomic number C) atomic number from electron number D) mass number from atomic number
A) like popcorn in a popper. B) like planets orbiting the sun. 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 are located in the left-most column of the periodic table B) they form negative ions C) they are usually gases D) the are extremely nonreactive
A) amount of a substance B) volume of a substance C) electric charge of a substance D) mass of a substance
A) atomic number B) atomic mass unit C) mass number D) isotope number
A) the number of valence electrons in atoms of the element B) its atomic mass C) how tightly atoms are packed in the element D) the ratio of protons to neutrons in atoms of the element
A) They have the same mass number B) their masses are identical C) They are isotopes of oxygen D) they do not have the same number of protons
A) element to element B) group to group C) column to column D) row to row
A) iodine, iron, nickel B) phosphorus, nitrogen, oxygen C) sodium, chromium, copper D) helium, carbon, gold
A) the discovery of subatomic particles. B) the discovery of the nucleus. C) the discovery of elements with predicted properties. D) the immediate acceptance by other scientists.
A) two B) none C) three D) four
A) decreases B) stays the same C) increases then decreases D) increases
A) carbon-12 atom B) neutron C) proton D) chlorine-35 atom
A) -1 B) 0 C) +1 D) -2
A) 1/18 B) 1/1840 C) 1 D) 0
A) period B) mass C) number of neutrons D) chemical properties
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-half the mass of a hydrogen atom C) one-fourth the mass of a lithium atom D) one-fifteenth the mass of a nitrogen-15 atom
A) They exist as single elements rather than molecules B) they are rare in nature C) they can form compounds with bright colors D) they are highly reactive
A) do not form compounds B) can conduct electric current only under certain conditions C) have large atomic masses but small atomic numbers D) are extremely hard
A) on the right B) in the middle C) on the left D) on the bottom
A) one gram of a pure substance B) one liter of a pure substance C) one mole of a pure substance D) one kilogram of a pure substance.
A) 35 B) 172 C) 79 D) 80
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