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