The whole tone scale in another example of a nondiatonic scale.  See Chromatic scale for a definition of nondiatonic.  The Whole tone scale is made up entirely of whole steps between each note, hence the name.

A – B – C# – D# – F – G – A

or

A# – C – D – F# – G# – A#

The whole tone scale is used more often then the chromatic scale and is used frequently in experimental or 20th century music, although it can be found in earlier music periods.