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