Q. Is there a period after an abbreviation of a country if it is terminating a sentence? “I went to U.K..”
A. Seriously, have you ever seen two periods in a row like that in print? If we told you to put two periods, would you do it? Would you set your hair on fire if CMOS said you should?
The editor of the Chicago Manual of Style’s monthly Q&A is Carol Fisher Saller. I enjoyed (and recommend) her book, The Subversive Copy Editor: Advice from Chicago (Or, How to Negotiate Good Relationships With Your Writers, Your Colleagues, and Yourself).
As a bonus, I’ll leave you with another of Saller’s classic Q&As:
Q. Oh, English-language gurus, is it ever proper to put a question mark and an exclamation mark at the end of a sentence in formal writing? This author is giving me a fit with some of her overkill emphases, and now there is this sentence that has both marks at the end. My everlasting gratitude for letting me know what I should tell this person.
A. In formal writing, we allow both marks only in the event that the author was being physically assaulted while writing. Otherwise, no.