Atomic Structure- Energy diff between levels

[rxy152]

Homework Statement

Consider the NaCl molecule, in which the atomic weights of Na and Cl are 23 and 37, respectively. The internuclear separation is 0.236 nm, and the ”spring constant” for vibrations is k = Mred ω^2 = 1 × 10^9 J/m^2 . Calculate the energy difference between adjacent vibrational levels. The value of h-bar is 1.055 × 10^−34 J · s. Answer in units of eV

Homework Equations

The Attempt at a Solution

I tried using reduced mass where m(red) = 23*37 / (23+37)= 14.18

Then plugged m(red) in the equation k = Mred ω^2 where i solved for ω = 8396

With ω, I used E=hbar * ω to get E = 8.8548E-31 J

= 5.527E-12 eV, which is wrong.

Plz Help!

 

[phyzguy]

Check your units. Are the masses of Na and Cl in kg?

 

[rxy152]

Check your units. Are the masses of Na and Cl in kg?

It doesn't state the units, which i thought was weird.

Here are some constants provided -
The value of h bar is 1.05457 × 10^−34 J · s ; the speed of light is 2.99799 × 10^8 m/s ; the value of h is 6.62607 × 10^−34 J · s ; the Rydberg constant for hydrogen is 1.09735 × 10^7 m −1 ; the Bohr radius is 5.29177 × 10^−11 m ; and the ground state energy for hydrogen 13.6057 eV .

 

[phyzguy]

It doesn't state the units, which i thought was weird.

You need to look up what "atomic weight" means, and how to calculate the mass of an atom (in kg) given its atomic weight.