title: confused about improper lists in Scheme
body: <p>I was wondering why     </p>
  
  <pre><code>'((atom1) . atom2)
  </code></pre>
  
  <p>is the improper List out of the following selections</p>
  
  <pre><code>'(atom1 . (atom2))
  '((atom1) . atom2)
  '(atom1 atom2)
  (cdr '(atom1))
  (cons 'atom1 '(atom2))
  </code></pre>