Q. I am surprised that you spell Ms (as in Ms Helen Jones) with a period (Ms. Helen Jones). Nothing is being abbreviated (as in Mr. or Mrs.). Our University Senate adopted plain Ms in its documents some time ago!
A. Chicago style is to use a period after “Ms.” even though it’s not technically an abbreviation, following Merriam-Webster, which suggests that “Ms.” is a shortened form combining “Miss” and “Mrs.”