A) the ratio of their masses is always the same. B) each element contributes an equal number of atoms. C) their masses are always equal. D) their volumes are always equal.
A) There is a dense, positively charged mass in the center of an atom. B) Negative and positive charges are spread evenly throughout an atom. C) Alpha particles have a positive charge. D) Gold is not as dense as previously thought.
A) concentrated at multiple sites in an atom. B) located in the space outside the nucleus. C) concentrated in the center of an atom. D) spread evenly throughout an atom.
A) proton B) neutron C) electron
A) Protons, neutrons, and electrons all have about the same mass. B) Neutrons have no charge and no mass. C) Unlike protons or neutrons, electrons have no mass. D) An electron has far less mass then either a proton or a neutron.
A) the charge on the electrons B) the number of neutrons C) the number of protons D) the mass of the neutron
A) atomic number B) isotope C) mass number D) charge
A) mass number from atomic number B) atomic number from mass number C) atomic number from electron 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 precise location of electrons in an atom B) the most likely locations of electrons in an atom C) the number of electrons in an atom D) the mass of the electrons in the atom
A) they are usually gases B) the are extremely nonreactive C) they are located in the left-most column of the periodic table D) they form negative ions
A) mass of a substance B) amount of a substance C) electric charge of a substance D) volume of a substance
A) atomic number B) mass number C) isotope number D) atomic mass unit
A) the ratio of protons to neutrons in atoms of the element B) the number of valence electrons in atoms of the element C) its atomic mass 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) They are isotopes of oxygen D) their masses are identical
A) column to column B) row to row C) group to group D) element to element
A) phosphorus, nitrogen, oxygen B) iodine, iron, nickel C) sodium, chromium, copper D) helium, carbon, gold
A) the discovery of the nucleus. B) the immediate acceptance by other scientists. C) the discovery of elements with predicted properties. D) the discovery of subatomic particles.
A) three B) none C) four D) two
A) increases then decreases B) increases C) decreases D) stays the same
A) carbon-12 atom B) proton C) neutron D) chlorine-35 atom
A) 0 B) +1 C) -1 D) -2
A) 1/18 B) 0 C) 1 D) 1/1840
A) chemical properties B) period C) mass D) number of neutrons
A) losing or gaining protons B) changing from one period to another C) losing or gaining electrons D) changing from lithium into fluorine
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 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) are extremely hard D) can conduct electric current only under certain conditions
A) in the middle B) on the left C) on the right D) on the bottom
A) one kilogram of a pure substance. B) one mole of a pure substance C) one liter of a pure substance D) one gram of a pure substance
A) 35 B) 79 C) 80 D) 172
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