Every one or everyone?

We use every one, written as two words, to refer back to a noun we have already mentioned:

I received more than a hundred letters from him while I was away and I’ve kept every one.

Everyone, written as one word, means ‘every person’:

We use every one of before pronouns and determiners:

There are 107 two-letter words in the dictionary and John Catto, an Aberdeen lorry driver, knows every one of them.
When Jenkins joined the bank, one of his first acts was to make every one of the bank’s employees reapply for their jobs.