Structure 1.3 Nuclear Atom, Emiision Spectrum, Ionisation Energy

Question 2

What is the definition of electronic configuration?

Answer 2

The distribution of electrons in different electron shells/orbits/energy levels.

Question 3

What do we call the regions in space where there is a high probability of finding an electron?

Answer 3

Atomic orbitals.

Question 4

According to modern views, how do electrons behave?

Answer 4

As quantum objects that behave as both particles and waves.

Question 5

What is Schrödinger’s wave function used for?

Answer 5

To describe the electrons in atoms in terms of their probability density.

Question 6

Fill in the blank: Electrons revolve around the nucleus of an atom in different _______.

Answer 6

electron shells.

Question 7

What does the principal quantum number describe?

Answer 7

The main energy level of an electron.

Question 8

True or False: The second quantum number describes the number of orbitals of each type.

Answer 8

False.

Question 9

What does the Pauli Exclusion Principle state?

Answer 9

No two electrons can have the same four quantum numbers.

Question 10

What principle states that the lowest energy levels must be filled first?

Answer 10

Aufbau Principle.

Question 11

What are the four quantum numbers that uniquely describe each electron in an atom?

Answer 11

• Principal quantum number
• Second quantum number
• Third quantum number
• Fourth quantum number

Question 12

What is Hund’s Rule?

Answer 12

Orbitals of the same energy are filled with electrons with the same spin before pairing occurs.

Question 13

What are the two notable exceptions to Hund’s rule?

Answer 13

• Chromium (Cr)
• Copper (Cu)

Question 14

What do the s, p, d, and f represent in electron configurations?

Answer 14

Types of orbitals.

Question 15

What does an atomic emission spectrum indicate?

Answer 15

Atoms of different elements emit light of distinctive colors when energized.

Question 16

Fill in the blank: The wave-particle duality of the electron was used by Erwin Schrödinger to develop the ______ model.

Answer 16

Quantum Mechanics.

Question 17

What is the maximum number of electrons that can occupy an s orbital?

Answer 17

2.

Question 18

What is the significance of the term ‘degenerate’ in relation to orbitals?

Answer 18

Orbitals of the same type have the same energy.

Question 19

What is the relationship between energy levels and the filling order of orbitals?

Answer 19

Orbitals are filled in order of increasing energy.

Question 20

Fill in the blank: The highest probability of finding electrons in a 2s orbital is at a distance _______ from the nucleus.

Answer 20

somewhat further away.

Question 21

What did De Broglie suggest about electrons?

Answer 21

Electrons can behave like waves.

Question 22

What is the role of quantum numbers in describing electrons?

Answer 22

They provide a unique description of each electron’s state.

Question 23

What is an atomic orbital?

Answer 23

A mathematical function describing the location and wave-like behavior of an electron.

Question 24

True or False: Electrons move about an atom in a definite path according to the wave mechanical model.

Answer 24

False.

Question 25

What is produced when an electric discharge is passed through a vapor of an element?

Answer 25

A distinctive colour is produced. ## Footnote This phenomenon helps in identifying elements.

Question 26

How can metals be identified in a flame test?

Answer 26

By the colour of the flame produced when their compounds are heated in a Bunsen burner. ## Footnote Different metals produce different flame colours.

Question 27

What has analysis of light emitted by different atoms provided insights into?

Answer 27

The electron configurations within the atom.

Question 28

What is electromagnetic radiation?

Answer 28

Energy travelling in waves.

Question 29

What two properties describe a wave?

Answer 29

Frequency (f) and wavelength (λ).

Question 30

What is the speed of light (c)?

Answer 30

3.0 x 10^8 m s^-1.

Question 31

What is the equation relating wavelength (λ), frequency (f), and the speed of light (c)?

Answer 31

λ = c/f.

Question 32

What is the entire range of frequencies of electromagnetic radiation called?

Answer 32

The electromagnetic spectrum.

Question 33

What is energy of a photon (E) related to?

Answer 33

Its frequency (E = hf), where h is Planck's constant.

Question 34

What is Planck's constant (h)?

Answer 34

6.6 x 10^-34 J s.

Question 35

What are the three types of spectrum produced?

Answer 35

* Continuous spectrum * Emission spectrum * Absorption spectrum

Question 36

What happens when light is refracted through a medium?

Answer 36

Different wavelengths of light come out at different angles, a process called dispersion.

Question 37

What occurs when a sample of gaseous hydrogen is heated or passes through an electric discharge?

Answer 37

Electrons absorb energy and move to a higher energy level.

Question 38

What is the ground state of an atom?

Answer 38

The lowest energy level occupied by electrons.

Question 39

What is the result of an atom returning from an excited state to the ground state?

Answer 39

It releases a fixed amount of energy in the form of electromagnetic radiation.

Question 40

What does each line in the emission spectrum correspond to?

Answer 40

A specific frequency/wavelength and energy transition between energy levels.

Question 41

What is the Balmer series?

Answer 41

The series of spectral lines in the visible spectrum of hydrogen.

Question 42

What is the most intense line in the emission spectrum of hydrogen?

Answer 42

The red part at 656 nm.

Question 43

What does the Rydberg equation describe?

Answer 43

The frequencies of spectral lines observed in hydrogen.

Question 44

What are the other series of spectral lines in the emission spectrum of hydrogen?

Answer 44

* Lyman series (UV region) * Paschen series (near IR region) * Brackett series (IR region) * Pfund series (IR region)

Question 45

What happens to spectral lines as energy levels increase?

Answer 45

The lines get closer together until they converge.

Question 46

What is the absorption spectrum of hydrogen?

Answer 46

Produced when photons are absorbed by electrons moving to higher energy levels.

Question 47

Who proposed the Bohr atomic model?

Answer 47

Niels Bohr in 1913.

Question 48

What does the Bohr model state about electrons?

Answer 48

Electrons occupy fixed energy levels assigned a principal quantum number.

Question 49

What is ionization?

Answer 49

The process of an electron breaking away from an atom.

Question 50

What are the limitations of Bohr's model?

Answer 50

* It cannot explain the line spectra of multi-electron atoms. * It assumes electrons are solid particles. * It does not account for electron wave-particle duality.

Question 51

Definition of FIRST ionisation energy?

Answer 51

Minimum energy required to remove one mole of valence electrons from one mole of gaseous atoms to form one mole of gaseous positive ions X —> X^+ + e

Question 52

Ionisation energy

Answer 52

Minimum energy require to remove electron out of a neutral atom or molecule in ground state

Question 53

Nuclear attraction depends on:

Answer 53

1. Atomic radius 2. Nuclear charge 3. Electron shielding

Question 54

When atomic radius increases, nuclear attraction

Answer 54

decreases

Question 55

When nuclear charge increases, nuclear attraction

Answer 55

Increases

Question 56

Define electron shielding

Answer 56

Shielding of outer electrons by inner electrons due to repulsion

Question 57

Increased electron shielding (due to increased electron shells), leads to __________ of nuclear charge

Answer 57

Decrease (S orbital greater shielding effect than p orbital)

Question 58

Trend of 1st IE across periods - drops

Answer 58

1. Next orbital - increases electron shielding in ______ energy level - ________ electron further away from nucleus —> help less strongly - LESS energy for removal 2. Pairing - extra electron paired up with another electron in ______ orbital - repulsive force between 2 paired up electrons - LESS energy required to remove one electron

Question 59

Explain sharp increase in IE between 2 electrons

Answer 59

1. State energy level of each electron (electron no. 1 would be in higher energy level than electron no. 3) 2. Higher no. electron closer to nucleus —> harder to remove