A) the ratio of their masses is always the same. B) their masses are always equal. C) each element contributes an equal number of atoms. D) their volumes are always equal.
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) 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) proton B) neutron C) electron
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 number of protons C) the number of neutrons D) the charge on the electrons
A) atomic number B) isotope C) charge D) mass number
A) mass number from atomic number B) atomic number from electron number C) isotope number from atomic number D) atomic number from mass number
A) like beach balls on water waves. B) like balls rolling down a hill. C) like planets orbiting the sun. D) like popcorn in a popper.
A) the mass of the electrons in the atom B) the most likely locations of electrons in an atom C) the precise location of electrons in an atom D) the number of electrons in an atom
A) they are located in the left-most column of the periodic table B) they are usually gases C) they form negative ions D) the are extremely nonreactive
A) volume of a substance B) mass of a substance C) amount of a substance D) electric charge of a substance
A) mass number B) atomic mass unit C) isotope number D) atomic number
A) the number of valence electrons in atoms of the element B) the ratio of protons to neutrons in atoms of the element C) its atomic mass D) how tightly atoms are packed in the element
A) their masses are identical B) they do not have the same number of protons C) They have the same mass number D) They are isotopes of oxygen
A) column to column B) row to row C) group to group D) element to element
A) iodine, iron, nickel B) phosphorus, nitrogen, oxygen C) helium, carbon, gold D) sodium, chromium, copper
A) the immediate acceptance by other scientists. B) the discovery of the nucleus. C) the discovery of elements with predicted properties. D) the discovery of subatomic particles.
A) three B) none C) two D) four
A) decreases B) increases then decreases C) increases D) stays the same
A) carbon-12 atom B) chlorine-35 atom C) neutron D) proton
A) -1 B) +1 C) 0 D) -2
A) 1 B) 1/1840 C) 0 D) 1/18
A) period B) number of neutrons C) mass D) chemical properties
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-half the mass of a hydrogen atom B) one-fifteenth the mass of a nitrogen-15 atom C) one-twelfth the mass of a carbon-12 atom D) one-fourth the mass of a lithium atom
A) they are rare in nature B) they are highly reactive C) They exist as single elements rather than molecules D) they can form compounds with bright colors
A) do not form compounds B) can conduct electric current only under certain conditions C) are extremely hard D) have large atomic masses but small atomic numbers
A) on the right B) in the middle C) on the bottom D) on the left
A) one liter of a pure substance B) one kilogram of a pure substance. C) one gram of a pure substance D) one mole of a pure substance
A) 80 B) 79 C) 172 D) 35
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