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) Alpha particles have a positive charge. 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) Gold is not as dense as previously thought.
A) located in the space outside the nucleus. B) concentrated in the center of an atom. C) concentrated at multiple sites in an atom. D) spread evenly throughout an atom.
A) neutron B) electron C) proton
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 number of neutrons B) the number of protons C) the charge on the electrons D) the mass of the neutron
A) atomic number B) mass number C) isotope D) charge
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 beach balls on water waves. D) like planets orbiting the sun.
A) the most likely locations of electrons in an atom B) the number of electrons in an atom C) the mass of the electrons in the atom D) the precise location of electrons in an atom
A) the are extremely nonreactive B) they are usually gases C) they form negative ions D) they are located in the left-most column of the periodic table
A) electric charge of a substance B) amount of a substance C) mass of a substance D) volume of a substance
A) atomic number B) isotope number C) atomic mass unit D) mass number
A) its atomic mass B) how tightly atoms are packed in the element C) the ratio of protons to neutrons in atoms of the element D) the number of valence electrons in atoms of the element
A) They have the same mass number B) they do not have the same number of protons C) They are isotopes of oxygen D) their masses are identical
A) element to element B) column to column C) group to group D) row to row
A) helium, carbon, gold B) iodine, iron, nickel C) sodium, chromium, copper D) phosphorus, nitrogen, oxygen
A) the discovery of elements with predicted properties. B) the discovery of subatomic particles. C) the discovery of the nucleus. D) the immediate acceptance by other scientists.
A) three B) four C) two D) none
A) stays the same B) decreases C) increases then decreases D) increases
A) carbon-12 atom B) neutron C) proton D) chlorine-35 atom
A) 0 B) -2 C) +1 D) -1
A) 1/1840 B) 0 C) 1/18 D) 1
A) period B) chemical properties C) mass D) number of neutrons
A) losing or gaining electrons B) changing from one period to another C) losing or gaining protons D) changing from lithium into fluorine
A) one-half the mass of a hydrogen atom B) one-fourth the mass of a lithium atom C) one-twelfth the mass of a carbon-12 atom D) one-fifteenth the mass of a nitrogen-15 atom
A) they are rare in nature B) They exist as single elements rather than molecules C) they are highly reactive D) they can form compounds with bright colors
A) can conduct electric current only under certain conditions B) have large atomic masses but small atomic numbers C) are extremely hard D) do not form compounds
A) on the left B) on the right C) on the bottom 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) 80 B) 172 C) 35 D) 79
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