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