I'm on OCR ^^
I'm not sure where your blue electron came from, I drew this, I think it's the same?
EDIT: Apologies for the very scruffy writing.
EDIT2: After looking at it again, my OH bonds wouldn't have a negative charge...I think I understand now. The electron from Ca pairs with the oxygen and the other electron of oxygen bonds with hydrogen. But that wouldn't have a negative charge? Arghh, confused.