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