Tushar 2.2 - Electronic Configuration

Question 1

What is EM spectrum and which is highest frequency and wavelength in it

Answer 1

Radio Waves (lowest frequency/energy + longest wavelength)
Microwaves
Infrared
Visible light
Ultra violet
X-rays
Gamma rays (highest frequency/energy + shortest wavelength)

Question 2

How are energy and wavelength related

Answer 2

Energy ∝ 1/Wavelength (energy is inversely proportional to wavelength)

Question 3

Equation linking c= vλ and E=hv

Answer 3

E = (h x c) / λ

Question 4

What is the meaning of ground state and how is the energy of electrons

Answer 4

• energy of electron in each shell is quantized (fixed)

- ground state = lowest energy level that the electron normally occupies

Question 5

How are photons released by electrons

Answer 5

• electron in ground state is excited (e.g. by electrical discharge), this moves the electron to a higher energy level
• electron is now in excited state
• when electron goes back down to a lower energy level, it emits a photon
• this will give one line in the line spectrum

Question 6

What photon is released depending on level electron falls back into. What does this show?

Answer 6

Electron falls back to level 1: UV released
Electron falls back to level 2: Visible light released
Electron falls back to level 3,4,5: Infra red released

shows that energy difference between n=1 > energy level between n=2 and any other energy level (as UV has highest energy)

Also proof for discrete energy levels

Question 7

What happens in the line spectrum when energy increases

Answer 7

Lines in the line spectrum get closer together/converge (proof that shells become closer as energy level increases)

Question 8

What is convergence limit

Answer 8

Lines in the line spectrum merge to form a continuum, at this point the electron can have any energy level (n = infinity), it is free from the influence of the nucleus

Question 9

What does the frequency of convergence limit show

Answer 9

ionisation energy

Question 10

Electron shells are

Answer 10

concentric and converging

Question 11

electrons are stored in

Answer 11

energy levels that increase in energy as you go away from the nucleus

Question 12

main energy level is called

Answer 12

principal quantum number

Question 13

Max electron in each main energy level is

Answer 13

2n^2

Question 14

What else is there other than main energy levels

Answer 14

there are also sub-energy levels. Subshell closest to nucleus fills up first as strongest electrostatic attraction

Question 15

What are the four different subshells and number of electrons that can fit in that subshell

Answer 15

s (2), p (6), d(10), f(14)

Question 16

Why does 3d have higher energy than 4s

Answer 16

As 3d orbitals are more compact than 4s orbitals, so there is a greater repulsion between the electrons

Question 17

What is an orbital

Answer 17

region of space with high probability of finding an electron

Question 18

Orbital can hold max + types of orbitals are

Answer 18

2 electrons

s, p, d, f

Question 19

How many orbitals in each main energy level

Answer 19

energy level 1
1 s orbital

energy level 2
1 s orbital and 3 p orbitals

energy level 3
1 s orbital and 3p orbitals and 5 d orbitals

energy level 4
1 s orbital and 3p orbitals and 5d orbitals and 7 f orbitals

Question 20

Electrons in orbitals have

Answer 20

opposite spins due to repulsion

Question 21

What is Hund’s rule

Answer 21

When have same energy orbitals, electrons fill all the orbitals singly before occupying them in pairs

Question 22

Aufbau principle

Answer 22

electrons fill lowest energy orbital first

Question 23

Unexpected electronic configurations and why is this

Answer 23

Chromium - [Ar]3d54s1
Copper - [Ar] 3d104s1

As more stable

Question 24

What is continuous spectrum

Answer 24

All colours merging into each other.

White light passing through prism forms this - dispersion