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 the electromagnetic spectrum?

Answer 7

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

Question 8

What is the order of the electromagnetic spectrum?

Answer 8

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

Question 9

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

Answer 9

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 10

What is the ground and excited state of an atom?

Answer 10

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 11

What is a photon?

Answer 11

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

Question 12

What are the Paschen, Balmer and Lyman series?

Answer 12

Paschen - falls to energy level 3 and emits IR
Balmer - falls to energy level 2 and emits visible light
Lyman - falls to energy level 1 and emits UV

Question 13

Why do lines converge at higher energies?

Answer 13

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

Question 14

What is the uncertainty principle?

Answer 14

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

Question 15

What is an energy level?

Answer 15

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

Question 16

What is a shell and sub-shell?

Answer 16

Shell - defined by the energy level.

Question 17

What are orbitals?

Answer 17

Holds 2 electrons with a defined energy state

Question 18

How many electrons can each energy level hold?

Answer 18

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

Question 19

What is the first energy level made out of?

Answer 19

1s orbital
- holds a maximum of 2 electrons

Question 20

What is the second energy level made out of?

Answer 20

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

Question 21

What is the third energy level made out of?

Answer 21

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

Question 22

What is Hund’s third rule?

Answer 22

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

Question 23

What is the Aufbau principle?

Answer 23

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

Question 24

What is the Pauli-exclusion principle?

Answer 24

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

Question 25

What is the electronic configuration of Cu and Cr?

Answer 25

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

Question 26

What are valence electrons?

Answer 26

Outer shell electrons

Question 27

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

Answer 27

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

Question 28

What happens when electrons fall back to lower energy levels?

Answer 28

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

Question 29

What happens when electrons are excited?

Answer 29

They jump up to higher energy levels

Question 30

What is ionization energy?

Answer 30

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

Question 31

How can we work out ionization energy using a graph?

Answer 31

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

Question 32

What equation do we use to work out ionization energy?

Answer 32

E = hf

Question 33

How do we work out ionization energy for 1 mole?

Answer 33

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

Question 34

What is successive ionization energy?

Answer 34

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

Question 35

What are key observations from successive ionization graphs?

Answer 35

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

Question 36

Why is there an increase in successive ionization energies?

Answer 36

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

Question 37

Why are there big jumps in ionization energy?

Answer 37

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 38

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

Answer 38

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 39

What is first ionization energy dependent on?

Answer 39

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

Question 40

Why does 1st ionization energy increase across a period?

Answer 40

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 41

Why does 1st ionization energy decrease down a group?

Answer 41

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 42

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

Answer 42

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 43

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

Answer 43

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.