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