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