hi, i was wondering, is there a bus from beijing to rizhao? if so, from where and what times?

Yes, there are two direct long-distance buses: one leaves from Lizeqiao Long-distance Bus Station at 08:10 with the fare od CNY210 per person and the other leaves from Yongdingmen Long-distance Bus Station at 20:30 with the fare of CNY240 per person.
The whole journey takes around 9 hours.

Thank you Shelly, do you know how to buy tickets? Is it possible to get them the day of?

The tickets can be bought at the bus station.
It is possible to get one on the same day, but it is hard. So it is suggested to book the ticket in advance.