How to add a tag to the HTML HEAD in Drupal 7

/**
 * Implements HOOK_preprocess_html().
 */
function hook_preprocess_html(&$vars) {

  // Build an array with configurations.
  $element = array(
    '#tag' => 'meta', // The html tag - meta/link/script
    '#attributes' => array(
      'name' => 'some_name',
      'content' => 'some_content',
    ),
  );

  drupal_add_html_head($element, 'your_key');
}