In ZFC the primitive "membership" usually has the statement "x is an element of

In ZFC the primitive "membership" usually has the statement "x is an element of

In ZFC the primitive "membership" usually has the statement "x is an element of the set y". My question is "is the element 'x'" of a set ever not a set within ZFC?

Read another response by Peter Smith, Richard Heck
Read another response about Mathematics