Unit 1 Inorganic Chemistry: Key Area 2 - Atomic orbitals, electronic configurations and the periodic table

Question 1

How can the discrete lines in an atomic spectra be explained?

Answer 1

The discrete lines observed in atomic spectra can be explained if electrons, like photons, also display the properties of both particles and waves.

Question 2

What are orbitals defined as?

Answer 2

An area where there is a 90% probability of finding an electron

Question 3

What are the 4 quantum numbers?

Answer 3

• Principle Quantum Number (n)
• Angular Momentum Quantum Number (l)
• Magnetic Quantum Number (m)
• Spin Magnetic Quantum Number (ms)

Question 4

What is the meaning of the Principle Quantum Number?

Answer 4

Energy level

Question 5

What is the meaning of the Angular Momentum Quantum number?

Answer 5

shape of the orbital

Question 6

What is the meaning of the Quantum number?

Answer 6

orientation

Question 7

What is the meaning of the Spin magnetic Quantum number?

Answer 7

Electron spin

Question 8

What is the fixed amount of energy of electrons within atoms called?

Answer 8

quanta

Question 9

What does the principle quantum number tell you about an atom?

Answer 9

The average relative distance of the electron from the nucleus. Is measure in n= 1,2,3,4…

Question 10

What does a higher value of n in the principle quantum number indicate?

Answer 10

The higher the value of n, the higher the potential energy associated with the shell and electrons are easier to remove from an atom

Question 11

If the value of n is 1, what is the value of l and the subsequent sub-shell?

Answer 11

l=0 and 1s

Question 12

If the value of n is , what is the value of l and the subsequent sub-shell?

Answer 12

l = 0/1 and 2s/2p

Question 13

If the value od n is 3, what is the value of l and the subsequent sub-shell?

Answer 13

l = 0/1, and 3s/3p, 3d

Question 14

If the value od n is 4, what is the value of l and the subsequent sub-shell?

Answer 14

l = 0/1, 2/3 and 4s/4p, 4d/4f

Question 15

How many atomic orbitals are there within a s sub shell?

Answer 15

1

Question 16

How many atomic orbitals are there within a p sub shell?

Answer 16

3

Question 17

What are the key features of the s orbital?

Answer 17

• spherical

- the s orbital in the first shell is smaller than the s orbital in the second shell

Question 18

What are the key features of the p orbital?

Answer 18

• each p orbital has two lobes
• three p orbitals have DEGENERATE (have the same energy as the other).
• they are aligned along perpendicular axes

Question 19

What are different about d orbitals?

Answer 19

the five d orbitals are DEGENERATE with each other but have higher energies than the s and p orbitals in the same shell

Question 20

What MUST be known about orbitals?

Answer 20

• The shapes of s and p orbitals
• Max number of electrons in any orbital
• Recognise d orbitals from diagrams
• Know that d has a different shape

Question 21

If the value of l is 0/1, what is the value of m and the type of atomic orbital?

Answer 21

m -1,0,+1 and 2s/2p

Question 22

If the value of l is 2, what is the value of m and the type of atomic orbital?

Answer 22

m = -2,-1,0,+1,+2 and 3s,3p,3d

Question 23

What value of s in the spin quantum number represents clockwise rotation?

Answer 23

S = +1/2

Question 24

What value of s in the spin quantum represents an anti- clockwise rotation?

Answer 24

S = -1/2

Question 25

What is the maximum amount of electrons an orbital can hold?

Answer 25

2

Question 26

In any orbital containing 2 electrons what must happen?

Answer 26

The electrons must be paired with the spins opposed represented as a box with a arrow pointing up and other pointing down, where the box represents an orbital

Question 27

What is the Pauli Exclusion Principle?

Answer 27

The Pauli Exclusion Principle states that - No two electrons in the same atom can have the same set of four quantum numbers. (no orbital can hold more than 2 electrons and the two electrons must have opposite spins)

Question 28

What are the three rules used to determine in which orbital, electrons of an element are located?

Answer 28

- The Aufbau Principle - Hund's Rule - The Pauli Exclusion Principle

Question 29

What does the Aufbau principle state?

Answer 29

That electrons fill the orbitals of increasing energy, meaning that the electrons will fill the orbitals starting with the orbital of lowest energy).

Question 30

What does Hund's rule state?

Answer 30

For degenerate orbitals, electrons will fill each orbital singly and with parallel spins, before pairing up to fill the orbitals.

Question 31

What happens to the sub-shell as the principle number increases?

Answer 31

The sub-shell will increase in energy.

Question 32

What is different about the 3d shell?

Answer 32

The 3d shell has greater energy than the 4s sub-shell.

Question 33

What is the ionisation energy?

Answer 33

The energy required to remove one mole of electrons from one mole of atoms in the gaseous state.

Question 34

Why between Be and B as well as Mg and Al is there a decrease in ionisation energy?

Answer 34

A full sub shell is a stable arrangement. For an element begins a new sub shell there is a decrease in stability.

Question 35

Why between N and O as well as P and S is there a decrease in ionisation energy?

Answer 35

A half full sub shell is also a relatively stable arrangement.

Question 36

How do molecules cope with excess electrons?

Answer 36

Extra orbitals are needed which come from empty d orbitals

Question 37

In order to predict molecular shape, what must be considered?

Answer 37

That all outer shell electrons (valence electrons) of the central atom repel each other. Must also consider bonding and non-bonding electron pairs.

Question 38

What is the process of predicting molecular shape called?

Answer 38

The Valence Shell Electron Pair Repulsion theory (VSEPR)

Question 39

In a neutral atom, what is the equation for electron pairs?

Answer 39

EP = no. of outer electrons + no. of bonding electrons / 2

Question 40

What is the equation for electron pairs with ions?

Answer 40

EP = no. of outer electrons + no. of bonded electrons (+ an electron for each negative charge and - an electron for each positive charge) / 2

Question 41

What is descending order of repulsion effect?

Answer 41

- non bonding / non bonding - non bonding / bonding - bonding / bonding