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