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