how to put markup around indiviual radio buttons
According to the Forms API matrix you can.  See https://api.drupal.org/api/drupal/developer!topics!forms_api_reference.html/7#radio  Have you tried some code to see if it does what you are looking for?

You can set '#options' for the radios to be a variable: 

$rads = array( 
  0 =&gt; '&lt;span&gt;' . t('Yes') . '&lt;/span&gt;', 
  1 =&gt; '&lt;span&gt;' . t('No') . '&lt;/span&gt;', );

$form['fldset8']['exp_radios'] = array(
 '#type' =&gt; 'radios', 
 '#options' =&gt; $rads, );