ELEMENTS
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The force that keeps electrons in orbit around the nucleus of an atom
is due to
    a) the intense gravity of the dense nucleus
   $b) the attraction of opposite electrical charges
    c) the magnetic field of the nucleus
    d) its orbital velocity

Another name for an isolated proton might be a
   $a) hydrogen ion
    b) hydrogen isotope
    c) helium ion
    d) neutron

The structure of the Bohr model of the atom most resembles the
structure of 
   $a) the solar system
    b) the Milky Way Galaxy
    c) the Universe
    d) a baseball

When the Sun and planets were created, there was no element
Poodlonium.  Labradorium atoms decay to form Poodlonium with a
half-life of 800 million years. If you find a rock that is one quarter
Labradorium, and three quarters Poodlonium, how old is the rock?
   a)	400 million years
   b)	800 million years
  $c)	1.6 billion years
   d)	3.2 billion years

If you could add a proton to an atom to create a new stable, isolated 
atom, you would have created 
   $a) a different element with a positive charge
    b) an isotope of the original element
    c) a fission reaction
    d) a neutron and a positron

If an isotope of a particular element has too many or         
too few neutrons in its nucleus, it is                        
    a) called a molecule.
    b) called an ion.
    c) no different than any other stable isotope.
   $d) unstable against radioactive decay.
                                                        
A rock's original composition included 4% of a radioactive element.
Now we measure only 1%.  About how many half-lives of that element
have passed since the rock was formed?  
    a) 3
    b) 96
    c) 4
   $d) 2

The stable element Zorox is only formed by decay of the radioactive
element Linoleum decays.  You analyze a rock to find that it has 3
times as much Zorox as Linoleum.  The age of the rock, expressed in
half-lives of Linoleum is
    a) 1
    b) 1/2
   $c) 2
    d) 3

Chemical elements heavier than iron are created primarily by  
the buildup of 
    a) colliding massive subatomic particles in the Big Bang
   $b) neutrons in atomic nuclei during supernova explosions
    c) proton decay reactions in empty space
    d) stable nuclear fusion in the cores of massive stars

Most of the heavy elements (everything except hydrogen and helium)
in the Earth were produced 
   a) in chemical reactions in the primitive oceans and atmosphere
   b) in nuclear reactions in the Sun
  $c) by stars that burned out before the solar system formed
   d) in the hot, dense, early universe

When the Universe is twice its current age, the fraction of atoms in
the Universe that are hydrogen 
    a) will be close to zero
    b) will be close to one
    c) should remain approximately constant
   $d) will continue decreasing