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