// $arSelect = array("ID", "NAME", "DATE_ACTIVE_FROM");
      // $arFilter = array("IBLOCK_ID" => 2, "ACTIVE_DATE" => "Y", "ACTIVE" => "Y");
      // $res = CIBlockElement::GetList(array(), $arFilter, false, array("nPageSize" => 50), $arSelect);
      // while ($ob = $res->GetNextElement()) {
      //             $arFields = $ob->GetFields();
      //             print_r($arFields);
      //       }

      $arSelect = array("ID", "IBLOCK_ID", "NAME", "DATE_ACTIVE_FROM", "PROPERTY_*"); //IBLOCK_ID и ID обязательно должны быть указаны, см. описание arSelectFields выше
      $arFilter = array("IBLOCK_ID" => 2, "ACTIVE_DATE" => "Y", "ACTIVE" => "Y");
      $res = CIBlockElement::GetList(array(), $arFilter, false, array("nPageSize" => 50), $arSelect);
      while ($ob = $res->GetNextElement()) {
            $arFields = $ob->GetFields();
            print_r($arFields);
            $arProps = $ob->GetProperties();
            print_r($arProps);