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