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