Atomic & Molecular Orbitals (U2,c1/6)(U1,c2/7)

Question 1

What is the Principal Quantum number?

Answer 1

n - Main energy level - The size and energy of the shell

Question 2

What is the Second Quantum number?

Answer 2

ℓ - Angular momentum - Shape of subshell (s, p, d, f)

Question 3

What is the Third Quantum number?

Answer 3

m - Magnetic - Orientation in space of the orbital

Question 4

What is the Fourth Quantum number?

Answer 4

s - Spin - Direction of spin

Question 5

What are the values of n?

Answer 5

1, 2, 3, 4, etc.

Question 6

What are the values of ℓ?

Answer 6

From 0 to (n-1)

Question 7

What are the values of m?

Answer 7

Any whole number between -ℓ and +ℓ

Question 8

What are the values of s?

Answer 8

+1/2 or -1/2

Question 9

What is Heisenberg’s Uncertainty Principle?

Answer 9

That it is impossible to state precisely the position & momentum of an electron at the same instant.

Question 10

What does it mean if orbitals are degenerate?

Answer 10

They have the same energy as each other.

Question 11

What does the Aufbau Principle say?

Answer 11

The orbitals of the lowest energy levels are always filled first. (“aufbau” from German “building up”)

Question 12

What does the Pauli Exclusion Principle say?

Answer 12

1. An orbital cannot contain more than two elecrions, and 2. They must have opposite spin.

Question 13

What does Hund’s Rule of Maximum Multiplicity say?

Answer 13

Where there are degenerate orbitals in a subshell, electrons fill each one singly, keeping spins parallel BEFORE spin pairing occurs.

Question 14

What IS an orbital?

Answer 14

A region of space in which it is very certain that an electron will be found - (the region in which the electron lives)

Question 15

How is a molecular orbital formed?

Answer 15

When the atomic, hybrid or other molecular orbitals merge to form a set of molecular orbitals.

Question 16

What is the basis of bonding between atoms?

Answer 16

The attraction of positive nuclei to negative electrons occupying molecular orbitals.

Question 17

What is the bonding molecular orbital?

Answer 17

The molecular orbital in which the electrons spend most of their time IN the region between the two nuclei.

Question 18

What is the antibonding molecular orbital?

Answer 18

The molecular orbital in which the electrons spend most of their time AWAY FROM the region between the two nuclei.

Question 19

How is a covalent bond formed? (in terms of orbitals)

Answer 19

Two half-filled atomic orbitals overlapping

Question 20

How is a σ bond formed?

Answer 20

When the atomic orbitals overlap end-on // along the axis of the bond

Question 21

How is a π bond formed?

Answer 21

When the atomic orbitals lie perpendicular to a σ bond overlap side-on

Question 22

Which kind of bond is stronger - σ or π bonds?

Answer 22

σ bonds (end-on overlap)

Question 23

How are σ and π bonds formed through hybridisation?

Answer 23

The 2s orbitals and three 2p orbitals combine during bonding to form FOUR new identical hybrid orbitals called sp3 orbitals.

Question 24

What determines where a compound fits into the bonding continuum?

Answer 24

The difference in electronegativity between bonded atoms.

Question 25

What determines the type of bonding in a molecule? (ionic, polar covalent, pure covalent)

Answer 25

The symmetry and the position of bonding orbitals between atoms.