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