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