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