A) each element contributes an equal number of atoms. B) their masses are always equal. C) their volumes are always equal. D) the ratio of their masses is always the same.
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) concentrated in the center of an atom. B) concentrated at multiple sites in an atom. C) located in the space outside the nucleus. D) spread evenly throughout an atom.
A) proton B) electron C) neutron
A) Unlike protons or neutrons, electrons have no mass. B) Protons, neutrons, and electrons all have about the same mass. C) Neutrons have no charge and no mass. D) An electron has far less mass then either a proton or a neutron.
A) the mass of the neutron B) the charge on the electrons C) the number of neutrons D) the number of protons
A) charge B) isotope C) atomic number D) mass number
A) atomic number from mass number B) mass number from atomic number C) isotope number from atomic number D) atomic number from electron number
A) like beach balls on water waves. B) like balls rolling down a hill. C) like planets orbiting the sun. D) like popcorn in a popper.
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) they are located in the left-most column of the periodic table B) they form negative ions C) they are usually gases D) the are extremely nonreactive
A) volume of a substance B) mass of a substance C) electric charge of a substance D) amount of a substance
A) atomic number B) isotope number C) atomic mass unit D) mass 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) they do not have the same number of protons B) They are isotopes of oxygen C) their masses are identical D) They have the same mass number
A) column to column B) group to group C) element to element D) row to row
A) phosphorus, nitrogen, oxygen B) sodium, chromium, copper C) helium, carbon, gold D) iodine, iron, nickel
A) the discovery of subatomic particles. B) the discovery of elements with predicted properties. C) the discovery of the nucleus. D) the immediate acceptance by other scientists.
A) three B) none C) two D) four
A) stays the same B) decreases C) increases then decreases D) increases
A) chlorine-35 atom B) proton C) carbon-12 atom D) neutron
A) +1 B) 0 C) -1 D) -2
A) 0 B) 1/18 C) 1 D) 1/1840
A) number of neutrons B) chemical properties C) period 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-twelfth the mass of a carbon-12 atom B) one-fifteenth the mass of a nitrogen-15 atom C) one-fourth the mass of a lithium atom D) one-half the mass of a hydrogen 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) can conduct electric current only under certain conditions B) have large atomic masses but small atomic numbers C) are extremely hard D) do not form compounds
A) in the middle B) on the bottom C) on the right D) on the left
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) 35 B) 79 C) 172 D) 80
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