Try this:
Code:
Sub test_Split_and_Align_1_tbl()
Application.ScreenUpdating = False
Dim oTbl As Table
Dim lngRow As Long, lngCol As Long
Dim oRng As Range
Set oTbl = Selection.Tables(1)
Set oRng = oTbl.Range
oRng.Start = oTbl.Columns(2).Cells(1).Range.Start
oRng.Select
Selection.Cells.Split 1, 2, False
For lngCol = 3 To oTbl.Columns.Count Step 2
oTbl.Columns(lngCol).Width = 48
Next lngCol
For lngCol = 4 To oTbl.Columns.Count Step 2
oTbl.Columns(lngCol).Width = 12
Next lngCol
For lngRow = 1 To oTbl.Rows.Count
For lngCol = 3 To oTbl.Columns.Count
If lngCol Mod 2 = 1 Then 'an odd column
oTbl.Cell(lngRow, lngCol).Range.ParagraphFormat.Alignment = wdAlignParagraphRight
Else
oTbl.Cell(lngRow, lngCol).Range.ParagraphFormat.Alignment = wdAlignParagraphLeft
End If
Next lngCol
Next lngRow
lbl_Exit:
Exit Sub
End Sub