public abstract class Element : ArcGIS.Desktop.Framework.Contracts.PropertyChangedBase, ArcGIS.Desktop.Mapping.IElement, System.ComponentModel.INotifyPropertyChanged, System.IComparable, System.IDisposable, System.IEquatable<Element>  

//Create a group with a single element at the root level of the contents pane.

//Find an existing element
Element titleElm = layout.FindElement("Title") as Element;

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //At 2.x - GroupElement groupWithSingleElementAtRoot = LayoutElementFactory.Instance.CreateGroupElement(layout, titleElm);
  //         groupWithSingleElementAtRoot.SetName("Group with single element at root"); 
  GroupElement groupWithSingleElementAtRoot = 
           ElementFactory.Instance.CreateGroupElement(layout, new List<Element>() { titleElm }, "Group with single element at root");
});

//Create a group with a list of elements at the root level of the contents pane.

//Find an existing elements
Element scaleBar = layout.FindElement("Scale Bar") as Element;
Element northArrow = layout.FindElement("North Arrow") as Element;
Element legend = layout.FindElement("Legend") as Element;

//Build a list and add the elements
List<Element> elmList = new List<Element>
{
  scaleBar,
  northArrow,
  legend
};

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //At 2.x - GroupElement groupWithListOfElementsAtRoot = LayoutElementFactory.Instance.CreateGroupElement(layout, elmList);
  //         groupWithListOfElementsAtRoot.SetName("Group with list of elements at root");
  GroupElement groupWithListOfElementsAtRoot = 
    ElementFactory.Instance.CreateGroupElement(layout, elmList, "Group with list of elements at root");
});