2. Atomic Structure

Question 1

Define isoelectronic

Answer 1

Atoms/ions that have the same number of electrons

Question 2

Define isotonic

Answer 2

Atoms/ions that have the same number of neutrons

Question 3

Define isotopes

Answer 3

Atoms of the same element with a different number of neutrons

Question 4

What are the characteristics of isotopes?

Answer 4

Same chemical properties but different physical properties

Question 5

Reading a mass spectrum: Define the x & y axes

Answer 5

x: Mass/charge ratio
y: Relative abundance

Question 6

Relationship between Energy & Wavelength

Answer 6

As E increases, wavelength decreases

Question 7

Relationship between Energy & Frequency

Answer 7

As E increases, frequency increases

Question 8

What is the purpose of the emission spectrum?

Answer 8

It is evidence for the existence of electrons in discrete energy levels which converge at higher energies

Question 9

Electromagnetic region associated with n=1

Answer 9

Ultraviolet

Question 10

Electromagnetic region associated with n=2

Answer 10

Visible light

Question 11

Electromagnetic region associated with n=3

Answer 11

Infrared

Question 12

What is the convergence limit?

Answer 12

The gap between the lines decrease until each series converges to a limit

Question 13

Describe the Bohr model in terms of energy levels, sub-levels, orbitals

Answer 13

Each energy level (1, 2, 3, …) has different numbers of sub-levels. Each sub-level has different numbers of orbitals, depending on which sub-level. Each orbital holds only 2 electrons.

Question 14

Shapes of orbitals

Answer 14

s: spherical
p: dumb-bell

Question 15

What is ground state?

Answer 15

The lowest energy state

Question 16

What are the 3 rules of electron arrangement in orbitals?

Answer 16

1. Aufbau principle
2. Hund’s rule
3. Pauli’s exclusion principle

Question 17

Define Aufbau principle

Answer 17

Electrons are added progressively to the orbitals starting with lowest energy
(Remember the arrow diagram)

Question 18

Define Pauli Exclusion Principle

Answer 18

Paired electrons can only be stable when they spin in opposite directions so that the magnetic attraction which results from their opposite spins counterbalances the electrical repulsion

Question 19

Define Hund’s Rule

Answer 19

When filling up a sub-level, each orbital must be occupied singly before they are occupied in pairs

Question 20

Exceptions to the Aufbau principle

Answer 20

Chromium & Copper

Question 21

How are electrons lost when forming cations

Answer 21

Lost from the orbital with the highest energy

Question 22

How are electrons added when forming anions

Answer 22

Added to the vacant orbital of highest energy

Question 23

Define 1st ionisation energy

Answer 23

The miniumum energy required in removing one mole of valence electrons from one mole of gaseous atoms to form 1 mole of singly positively charged gaseous ion

Question 24

What are the 2 factors affecting ionisation energy?

Answer 24

1. Nuclear charge

2. Shielding Effect

Question 25

Explain in detail how nuclear charge affects ionisation energy

Answer 25

The greater the nuclear charge, the greater the electrostatic force of attraction between the positively charged nucleus and negatively charged electrons, therefore the greater the ionisation energy

Question 26

Explain in detail how the shielding effect by inner electrons work

Answer 26

Electrons in inner shells repel valence electrons, increasing the shielding effect of the electrostatic forces of attraction of the nucleus on the valence electron, therefore lowering ionisation energy

Question 27

Explain why successive ionisation energies of an atom increase with the removal of each electron

Answer 27

An increasing amount of energy is required to remove successive electrons from an increasingly positive ion due to increasing electrostatic forces of attraction between nucleus and the valence electrons

Question 28

General trends in 1st ionisation energy

Answer 28

Increases across period, decreases down a group