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