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