A) their volumes are always equal. B) each element contributes an equal number of atoms. C) their masses are always equal. D) the ratio of their masses is always the same.
A) Gold is not as dense as previously thought. B) Negative and positive charges are spread evenly throughout an atom. C) There is a dense, positively charged mass in the center of an atom. D) Alpha particles have a positive charge.
A) concentrated at multiple sites in an atom. B) spread evenly throughout an atom. C) located in the space outside the nucleus. D) concentrated in the center of an atom.
A) electron B) proton C) neutron
A) Unlike protons or neutrons, electrons have no mass. B) An electron has far less mass then either a proton or a neutron. C) Neutrons have no charge and no mass. 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) atomic number B) isotope C) charge D) mass number
A) mass number from atomic number B) atomic number from electron number C) isotope number from atomic number D) atomic number from mass number
A) like popcorn in a popper. B) like beach balls on water waves. C) like balls rolling down a hill. D) like planets orbiting the sun.
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 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 mass unit B) atomic number C) isotope number D) mass number
A) the ratio of protons to neutrons in atoms of the element B) how tightly atoms are packed in the element C) its atomic mass D) the number of valence electrons in atoms of the element
A) they do not have the same number of protons B) their masses are identical C) They are isotopes of oxygen D) They have the same mass number
A) row to row B) group to group C) element to element D) column to column
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 the nucleus. C) the discovery of subatomic particles. D) the discovery of elements with predicted properties.
A) three B) two C) none D) four
A) increases B) decreases C) stays the same D) increases then decreases
A) proton B) chlorine-35 atom C) carbon-12 atom D) neutron
A) -2 B) 0 C) +1 D) -1
A) 1 B) 0 C) 1/18 D) 1/1840
A) period B) chemical properties C) number of neutrons D) mass
A) losing or gaining protons B) losing or gaining electrons C) changing from one period to another D) changing from lithium into fluorine
A) one-twelfth the mass of a carbon-12 atom B) one-fourth the mass of a lithium atom C) one-fifteenth the mass of a nitrogen-15 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) have large atomic masses but small atomic numbers B) can conduct electric current only under certain conditions C) are extremely hard D) do not form compounds
A) on the left B) in the middle C) on the bottom D) on the right
A) one kilogram of a pure substance. B) one liter of a pure substance C) one gram of a pure substance D) one mole of a pure substance
A) 79 B) 35 C) 172 D) 80
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