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