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