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) 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) Gold is not as dense as previously thought. D) Alpha particles have a positive charge.
A) concentrated in the center of an atom. B) spread evenly throughout an atom. C) located in the space outside the nucleus. D) concentrated at multiple sites in an atom.
A) electron B) proton C) neutron
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 mass of the neutron B) the charge on the electrons C) the number of neutrons D) the number of protons
A) atomic number B) mass number C) isotope D) charge
A) mass number from atomic number B) isotope number from atomic number C) atomic number from mass number D) atomic number from electron 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 most likely locations of electrons in an atom B) the mass of the electrons in the atom C) the number of electrons in an atom D) the precise location of electrons in an atom
A) they are usually gases B) the are extremely nonreactive C) they form negative ions D) they are located in the left-most column of the periodic table
A) volume of a substance B) amount of a substance C) electric charge of a substance D) mass of a substance
A) mass number B) atomic mass unit C) isotope number D) atomic number
A) its atomic mass B) how tightly atoms are packed in the element C) the number of valence electrons in atoms of the element D) the ratio of protons to neutrons in atoms of the element
A) They are isotopes of oxygen B) they do not have the same number of protons C) their masses are identical D) They have the same mass number
A) column to column B) element to element C) group to group D) row to row
A) sodium, chromium, copper B) helium, carbon, gold C) iodine, iron, nickel D) phosphorus, nitrogen, oxygen
A) the discovery of elements with predicted properties. B) the discovery of subatomic particles. C) the discovery of the nucleus. D) the immediate acceptance by other scientists.
A) two B) four C) three D) none
A) decreases B) increases C) stays the same D) increases then decreases
A) chlorine-35 atom B) carbon-12 atom C) proton D) neutron
A) +1 B) 0 C) -2 D) -1
A) 0 B) 1/18 C) 1/1840 D) 1
A) chemical properties B) number of neutrons C) period D) mass
A) changing from lithium into fluorine B) losing or gaining electrons C) losing or gaining protons D) changing from one period to another
A) one-twelfth the mass of a carbon-12 atom B) one-half the mass of a hydrogen atom C) one-fourth the mass of a lithium atom D) one-fifteenth the mass of a nitrogen-15 atom
A) they are highly reactive B) They exist as single elements rather than molecules C) they can form compounds with bright colors D) they are rare in nature
A) have large atomic masses but small atomic numbers B) are extremely hard C) can conduct electric current only under certain conditions D) do not form compounds
A) on the bottom B) on the left C) in the middle D) on the right
A) one mole of a pure substance B) one kilogram of a pure substance. C) one liter of a pure substance D) one gram of a pure substance
A) 80 B) 172 C) 35 D) 79
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