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