Add Space in Html string value using C# in ASP.Net

  <div>
        <div class="row">
            <div class="tab_container1">
                <div id="menu" runat="server">
                </div>
            </div>
        </div>
    </div>

 protected void Fillmenu()
    {

        clsTopic objTopic = new clsTopic(true);
        string strHtm1 = string.Empty;
        int i = 0;
        objTopic.getAllDatas();
        if (objTopic.ListclsTopic.Count > 0)
        {
            for (i = 0; i < objTopic.ListclsTopic.Count; i++)
            {
                strHtm1 +="<span>"+objTopic.ListclsTopic[i].TopicID +"<style='padding:10px'>"+objTopic.ListclsTopic[i].TopicName+"</span>";
            }
        }
        menu.InnerHtml = strHtm1;
    }
}

i want space etwwen this two name 

1Drama  7Ronak

like this