I'm having a lot of trouble with two of my homework problems tonight. I have been completely through my textbook and all over the internet, but I can't find what I'm looking for anywhere. I have no idea where to even begin on the following two problems, so if someone could just give me a push in the right direction (like an equation or something), I'd greatly appreciate it!

1. Calculate the root-mean-square (standard deviation) displacement of the nuclei of

^{12}C

^{16}O in the ground state and compare it to the equilibrium bond length of 112.832 pm. (HINT: <x>=0) Use ?=(k?/?

^{2})

^{1/2} and k=1903 kg/s

^{2}.

2. Calculate the value of <r> for the n=2, l=1, m

_{l}=0 state and the n=2, l=0, m

_{l}=0 state of the hydrogen atom.

Any help at all would be appreciated...thank you so much in advance!