S1.3 - electronic configuration

Question 1

What is an emission spectra?

Answer 1

Emission spectra are produced by atoms emitting photons when electrons in excited states return to lower energy levels.

Question 2

What is the line emission spectrum of hydrogen?

Answer 2

Provides evidence for the existence of electrons in discrete energy levels which converge at higher energies.

Question 3

What is an absorption spectra?

Answer 3

Absorption spectra are produced by atoms absorbing photons when electrons in lower energy levels jump up to higher energy levels and become excited.

Question 4

How do atoms give out different colors?

Answer 4

Atoms are heated in a Bunsen Burner to produce different colored flames

Question 5

What is frequency?

Answer 5

Frequency - number of waves passing a point per second.

Question 6

How do you work out wave speed?

Answer 6

Wave speed = frequency x wavelength

Question 7

What is emitted when atoms fall to energy levels 1, 2 and 3?

Answer 7

3 - Paschen series - emits infrared radiation (IR)
2 - Balmer series - emits visible light
1 - Lyman series - emits ultraviolet (UV)
Acronym - I SEE U - IR, Visible, UV

Question 8

What transition in the line emission of hydrogen gives the highest energy change?

Answer 8

Transitions to energy level 1, in the ultraviolet region of the spectrum.

Question 9

What is the electromagnetic spectrum?

Answer 9

A spectrum of different types of waves with increasing frequency and decreasing wavelength from left to right.

Question 10

What is the order of the electromagnetic spectrum?

Answer 10

Radio waves, Microwaves, Infrared, Visible, UV, X-ray, Gamma ray

Question 11

What is the difference between a continuous and a line spectrum?

Answer 11

Continuous spectrum - shows an unbroken sequence of frequencies , such as the visible light spectrum - shows all frequencies
Line spectrum - has only certain frequencies of light because it is produced by excited atoms as they fall back to a lower energy level.

Question 12

What is the ground and excited state of an atom?

Answer 12

Ground state - lowest energy and most stable arrangement where electrons is closest to the nucleus
Excited state - highest energy level with least stable arrangement where the electron is the furthest from the nucleus

Question 13

What is a photon?

Answer 13

A packet of light which corresponds to a particular wavelength and frequency.

Question 14

What are Planck’s equations?

Answer 14

E(electron) = E(photon) = h x f
h = Planck’s constant

Question 15

Why do lines converge at higher energies?

Answer 15

As the energy level increases, the energy levels between adjacent levels decreases, causing the spectral lines to converge at higher energies.

Question 16

What is the uncertainty principle?

Answer 16

We cannot know the certain location of an electron and are located in orbitals where there is high probability of finding an electron

Question 17

What is an energy level?

Answer 17

Shells around the nucleus that contain sub-shells in a specific shape

Question 18

What is a shell and sub-shell?

Answer 18

Shell - defined by the energy level.

Question 19

What are orbitals?

Answer 19

Holds 2 electrons with a defined energy state

Question 20

How many electrons can each energy level hold?

Answer 20

s = 2
p = 6
d = 10
f = 14

Question 21

What is the first energy level made out of?

Answer 21

1s orbital
- holds a maximum of 2 electrons

Question 22

What is the second energy level made out of?

Answer 22

2s orbital and three 2p orbitals
- holds a maximum of 8 electrons

Question 23

What is the third energy level made out of?

Answer 23

3s, three 3p orbitals and two 3d orbitals
- holds a maximum of 18 electrons

Question 24

What is Hund’s third rule?

Answer 24

Electrons fill up empty orbitals first before filling up occupied orbitals.

Question 25

What is the Aufbau principle?

Answer 25

Electrons are placed into lowest energy levels first.
- This can be illustrated by an arrow-in-box diagram?

Question 26

What is the Pauli-exclusion principle?

Answer 26

No more than 2 electrons can occupy 1 orbital and they must spin in opposite directions to reduce repulsion.

Question 27

What is the electronic configuration of Cu and Cr?

Answer 27

Cu = 1s2, 2s2, sp6, 3s2, 3p6, 3d10, 4s1
Cr = 1s2, 2s2, sp6, 3s2, 3p6, 3d5, 4s1

Question 28

What are valence electrons?

Answer 28

Outer shell electrons

Question 29

What does the limit of convergence in an emission spectra correspond to?

Answer 29

Limit of convergence in an emission spectra corresponds to ionization energy.

Question 30

What happens when electrons fall back to lower energy levels?

Answer 30

Gives out energy, which depends on the level it falls on

Question 31

What happens when electrons are excited?

Answer 31

They jump up to higher energy levels

Question 32

What is ionization energy?

Answer 32

Ionization energy - energy needed to remove 1 mole of electrons from 1 mole of atoms in their gaseous state

Question 33

How can we work out ionization energy using a graph?

Answer 33

F - convergence, which occurs when the line intercepts the x-axis
H - Planck’s constant (6.63 x 10^-34)

Question 34

What equation do we use to work out ionization energy?

Answer 34

E = hf

Question 35

How do we work out ionization energy for 1 mole?

Answer 35

E = hf x Avogadro’s constant (6.02 x 10^23)

Question 36

What is successive ionization energy?

Answer 36

Successive ionization energy - energy needed to remove an extra electron, from a positive ion.

Question 37

What are key observations from successive ionization graphs?

Answer 37

1) There is an increase in successive ionization energies.
2) There are big jumps in ionization energies?

Question 38

Why is there an increase in successive ionization energies?

Answer 38

As more and more electrons are removed from the atom, the atom itself becomes more charged, making it more difficult to remove.

Question 39

Why are there big jumps in ionization energy?

Answer 39

There are jumps when electrons are removed from increasingly closer shells to the nucleus, where it will be harder to remove the electrons as the electrons are closer to the + charge in the nucleus.

Question 40

Why is there a big jump between 9th and 10th ionization energy of Aluminium?

Answer 40

Jump between 9th and 10th ionization energies in Al shows that the 10th electron is more difficult to remove than expected, suggesting that the energy level is divided into 2 sub-levels, providing evidence of the existence of sub-shells.

Question 41

What is first ionization energy dependent on?

Answer 41

1) Charge on the nucleus
2) Distance of the outer electron from the nucleus
3) Electrons between outer electron and nucleus

Question 42

Why does 1st ionization energy increase across a period?

Answer 42

Across the period, ENC increases as proton number increases, and the electrons in the valence shell are more strongly attracted to the positive nucleus, and therefore requires more energy to overcome.

Question 43

Why does 1st ionization energy decrease down a group?

Answer 43

Down the group, more shells are added, increasing the shielding between the valence electrons and the nucleus, leading to less attraction between the electrons and nucleus so less energy is required too remove the electron.

Question 44

Why does B have a lower 1st IE than Be, despite having a higher nuclear charge?

Answer 44

The electron removed from B is in a partially filled 2p orbital, which requires less energy than removing an electron from the full and stable 2s orbital in Be.

Question 45

Why does O have a lower 1st IE than N, despite having a higher nuclear charge?

Answer 45

The electron removed from O is in a partially filled 2p orbital, where the electrons are starting to experience a repulsion from paired electrons in this orbital. This requires less energy than removing it from the half-full and semi-stable 2p orbital that the electron is being removed from in N.