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