[Grammar] on the morning of Monday or in the morning of Monday?

[Jeff Yin]

"The party is on the morning of Monday" or "The party is in the morning of Monday"?
I've asked some native speakers, but they just said it is strange to say both ways.
Are the two sentences both correct?

 

[Rover_KE]

No.

The party is on Monday morning.

 

[emsr2d2]

1. "The party is on the morning of Monday." [STRIKE]or[/STRIKE]
2. "The party is in the morning of Monday."
[STRIKE]?[/STRIKE]

I've asked some native speakers, but they just said [STRIKE]it is[/STRIKE] both sentences are [STRIKE]strange[/STRIKE] unnatural. [STRIKE]to say both ways.[/STRIKE]
Are both the [STRIKE]two[/STRIKE] sentences [STRIKE]both[/STRIKE] correct?

See my changes above. It's helpful to number your sentences, rather than try to make a question out of them.