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