2. Quantum-Mechanical model of an atom

Question 1

How Does the Quantum Mechanical Model of an

Atom Explain Atomic Spectra?

Answer 1

• Each line on an the emission spectrum corresponds to electron transition btn energy levels of an atom
• when an atom is excited it transition from a lower energy orbital to a higher energy orbital
• when an atom is “relaxed” it transition from a higher energy orbital to a lower energy orbital.

Question 2

def btn state and orbital

Answer 2

• orbital is defined by a set of quantum numbers (n, l, ml)

- state is a set of quantum numbers (n, l, ml, ms).

Question 3

Probability density

Radial distribution function

Answer 3

• indicates the region that an electron is likely to be found.

-gives the probability of finding an electron “dr” distance from the nucleus.
Note: in radial, the probabilty fo finding an electron at the nucleus (r = 0) is zero, and it’s maximum at a certain distance from the necleus.

Question 4

Sizes and Shapes of s-orbtals

Answer 4

the angular part of the wave function determines the shape of the orbital.
- the “ns” orbitals have (n-1) or (n-l-1) radial nodes.

Note: Total number of nodes is always (n-1) for s, p, and d.

Question 5

Can an electron in the p-orbital be found at the nucleus

- Also can we find a pz orbital in the xy plane

Answer 5

• The angular nodal plan in p-orbitals passes through the nucleus, so an electron can never be found at the nucleus
• pz orbital can’t be found in xy plane. py orbital can’t be found in xz plan, and so forth.