At the end of the Magen Avot prayer, commonly recited in shul Friday night, the last few words end in the phrase,
לעם מדושני עונג זכר למעשה בראשית
However, in the nighttime Kiddush, the phrase is:
באהבה וברצון הנחילנו זכרון למעשה בראשית
Is there a difference in their meaning between זכר and זכרון? As far as I know, both seem to mean "Remembrance".
Why is each term used in its place? What meaning or nuance is being conveyed that makes that term more appropriate than the other one?