The wave function of an orbital of H-Atom is given by: psi=((sqrt q)/(81 sqrt pi))(1/a_0)^(3/2)(6-r/a_0)(r/a_0)e^(-r/(3a_0) )* sin theta sin phi Then find the orbital ?

1) 2s
2) 3p_y
3) 3d_(z^2)
4) 2p_x

Is it the 2s???

1 Answer
Jul 13, 2017

There is no 2s in here at all. If there were, then there would be an e^(-r//2a_0) term, as well as a (2 - r/a_0) term. Neither of those are in here.

CHECKING THE ANGULAR NODES

Furthermore, here's a relatively easy way to verify that you have a p orbital:

![https://upload.wikimedia.org/](useruploads.socratic.org)

This wave function given goes to zero when the angular component, which contains sinthetasinphi, uses the angles (theta,phi) = (0^@, 0^@) or (theta,phi) = (180^@ , 180^@).

When theta = 0^@, 180^@, we are along the z axis. When phi = 0^@, 180^@, we are along the x axis. Together, the two angle combinations form a nodal plane in the xz plane, as there would be for a 3p_y atomic orbital.


VERIFYING WHAT ORBITAL THIS BELONGS TO

What you'll have to do is separate the wave function into its radial and angular components. This takes practice and you should reference your text to check if possible...

You gave:

psi=((sqrt color(red)(q))/(81 sqrt pi))(1/a_0)^(3//2)(6-r/a_0)(r/a_0)e^(-r//3a_0 )* sin theta sin phi

This has to be the 3p_y atomic orbital wave function.

  • It's the only wave function that contains sinthetasinphi in its angular component.
  • It contains a (6 - r/a_0), unique to the 3p radial wave function.
  • It contains an 81 in its normalization constant, unique to atomic orbitals of n = 3.

But let's check if it matches...

The actual 3py wave function for a hydrogen-like atom is (Inorganic Chemistry, Miessler et al., 5th ed.):

psi_(3,1,-1)(r,theta,phi)

= R_(31)(r) Y_(1)^(-1)(theta,phi)

= overbrace(1/(81sqrt3) ((2Z)/(a_0))^(3//2) (6 - (Zr)/(a_0))((Zr)/(a_0)) e^(-Zr//3a_0))^(R_(nl)(r) ("Radial")) cdot overbrace(1/2 sqrt(3/pi) sinthetasinphi)^(Y_(l)^(m_l)(theta,phi)("Angular"))

For hydrogen atom then, Z = 1, so this simplifies to:

= overbrace((cancel(2)cdot sqrt2)/(81cancel(sqrt3)) ((1)/(a_0))^(3//2) (6 - (r)/(a_0))((r)/(a_0)) e^(-r//3a_0))^(R_(nl)(r) ("Radial")) cdot overbrace(1/cancel(2) sqrt(cancel(3)/pi) sinthetasinphi)^(Y_(l)^(m_l)(theta,phi)("Angular"))

= color(blue)(overbrace(sqrt2/(81 sqrt(pi)) (1/(a_0))^(3//2) (6 - (r)/(a_0))((r)/(a_0)) e^(-r//3a_0))^(R_(nl)(r) ("Radial")) cdot overbrace(sinthetasinphi)^(Y_(l)^(m_l)(theta,phi)("Angular"))

I didn't change anything; all I did was take two already-separated components from my textbook, combine them together, and cancel out terms that have ratios of 1.

It's the same wave function that I first referenced, and evidently, this matches the 3p_y wave function exactly. I also think you had a typo so that sqrtq was supposed to be sqrt2.