A. What quantum number of the hydrogen atom comes closest to giving a 61-nm-diameter electron orbit? b. What are the electron's speed and energy in this state?

a

b

Explanation:

From the question we are told that

   The diameter is

Generally the radius electron orbit  is mathematically represented as

=>  

This radius can also be represented mathematically  as

Here n is the quantum number and is  the Bohr radius with a value

So

=>  

Generally the angular momentum of the electron is mathematically represented as

Here  h is the Planck constant and the value is  

          m is the mass of the electron with values

         So