Schrodinger wave equation / quantum no.s / orbitals

Question 1

What is the mathematical function which describes an e- as a wave within a region of space?

Answer 1

Ψ (wavefunction).

Question 2

What does Ψ represent in schrodinger’s wave equation?

Answer 2

It is a mathematical function ( a wavefunction) which describes an e- as a wave within a region of space.

Question 3

What does Ψ² represent in schrodinger’s wave equation and what does this mean?

Answer 3

The probability of finding an e- at a given region.

Since the wavefunction is squared, it means that the probability will always be zero or positive.

Question 4

What does 95%+ probability mean in terms of e-s?

Answer 4

If the probability is 95%+, then it is very likely that an e- will be found in this region.

This region is called an atomic orbital.

Question 5

Define an atomic orbital in terms of probability using schrodinger wave equation.

Answer 5

An atomic orbital is a region defined by a probability of 95%+, where it is very likely that an e- will be found.

Question 6

What is a quantum number?

Answer 6

It uniquely identifies / labels each inidividual electron in an atomic orbital of any atom.

Question 7

How can an individual electron be identified within an atomic orbital in any atom?

Answer 7

Use a series of quantum numbers.

E.g. 1s²

Question 8

What does the schrodinger wave equation or quantum numbers try to achieve?

Answer 8

It tries to find and uniquely label / identify each electron in atomic orbital of any atom.

Practical attempt on theory at actually finding an e- in a given space.

Question 9

What are the four different types of atomic orbitals?

Answer 9

s, p, d, f

Question 10

Total number of electrons held in each type of orbital?

Answer 10

s = 2

p = 6

d = 10

f = 14

Question 11

What are the sub orbitals in p-orbital?

Answer 11

p^x = 2 e-s each

p^y = 2 e-s each

p^z = 2 e-s each

Question 12

How many e-s can be held in a sub-orbital and what type of e-s?

Answer 12

2 e-s with opposite spins.

Question 13

What is the shape of an s orbital?

Answer 13

spherically symmetric

Question 14

What is the shape of p orbitals?

Answer 14

p orbitals are aligned mutually perpendicular along axes x, y and z

Question 15

What does electronic configuration of an atom mean?

Answer 15

Filling up of orbitals with electrons in an atom.

Question 16

What is the order of energy of orbitals starting from shell no. 1 to 4?

Answer 16

1s > 2s > 2p >3s > 3p > 4s > 3d > 4p

Question 17

How many s, p, d and f orbitals are there?

Answer 17

s orbital = 1

p orbital = 3

d orbital = 5

f orbital = 7

Question 18

Why is 4s orbital filled before 3d?

Answer 18

Bc 4s orbital has lower energy than 3d therefore it is filled up first.

Question 19

What are the three rules when filling up available atomic orbitals with electrons (electronic configuration)?

Answer 19

1. Pauli exclusion principle = each e- in an atom has an unique set of 4 quantum numbers.
2. The aufbau “building” principle = lowest energy orbital is filled first then next lowest e.g. 1s then 2s
3. Hund’s rule = when filling a set of degenerate orbitals , FIRST fill in each orbital with single electrons until ALL denegerate orbitals have one e- with parallel spins.

THEN pair up e-s with opposite spins in each degenerate orbital.

Question 20

What is a degenerate orbital?

Answer 20

Orbitals with equal energy.

Question 21

Incorrect use of Hund’s rule example.

Answer 21

1s², 2s², 2p_x², 2p_y¹

Question 22

Nitrogen = 7 electrons.

Show its electronic configuration with only Aufbau principle.

Answer 22

1s², 2s², 2p³

Question 23

Nitrogen = 7 electrons.

Show its electronic configuration with both Aufbau principle and Hund’s rule.

Answer 23

1s2, 2s2, 2p_x¹, 2p_y¹​, 2p_z¹​

Question 24

Explain the pauli exclusion principle and what is it used for?

Answer 24

Used in electronic configuration i.e. filling up available atomic orbitals with e-s.

Each e- in an atom has an unique set of 4 quantum numbers.

Question 25

Explain the aufbau “building” principle and what is it used for?

Answer 25

Lowest energy orbital is filled first then next lowest e.g. 1s then 2s.

Used in electronic configuration i.e. filling up available atomic orbitals with e-s.

Question 26

Explain Hund’s rule and what is it used for?

Answer 26

Used in electronic configuration i.e. filling up available atomic orbitals with e-s.

When filling a set of degenerate orbitals , FIRST fill in each orbital with single electrons until ALL denegerate orbitals have one e- with parallel spins.

THEN pair up e-s with opposite spins in each degenerate orbital.

AKA.

Singly fill all degenerate orbital with 1 e- each then pair up with opposite spins.