Atomic Structure

Question 1

When did John Dalton develop his atomic theory?

Answer 1

1808

Question 2

Michael Faraday and Davy’s work

Answer 2

With their work on electrolysis, they discovered that matter is made up of electrical charges, thus laying the foundation for the thought that atoms may, after all, be divisible.

Question 3

JJ Thomson’s work

Answer 3

He confirmed the presence of negatively charged components of matter in his popular discharge tube experiments

Question 4

What did Thomson describe his negatively charged components of matter as?

Answer 4

Cathode rays

Question 5

The charge to mass ratio of cathode rays are constant. True or false?

Answer 5

True

Question 6

What is the value of the charge-to-mass ratio of cathode rays?

Answer 6

1.76 x 10^11 C/kg

Question 7

Who carried out the oil drop experiment?

Answer 7

Robert Millikan

Question 8

Who calculated the exact mass on an electron?

Answer 8

Robert Millikan

Question 9

How did Millikan calculate the exact mass on an electron?

Answer 9

He used the charge-mass constant

Question 10

What is the charge on an electron?

Answer 10

1.6 x 10^-19

Question 11

What is the mass of an electron?

Answer 11

9.11 x 10^-31 kg

Question 12

What did Ernest Rutherford describe?

Answer 12

Protons

Question 13

Who developed the planetary model of the atom?

Answer 13

Ernest Rutherford

Question 14

Describe Rutherford’s experiment

Answer 14

It was an alpha scattering experiment where he bombarded a thin gold foil with alpha particles and observed their pattern. He concluded that they had positive charges concentrated in the centre

Question 15

What did Henry Moseley do?

Answer 15

…He determined the number of protons in the nucleus of an atom from his work involving the bombardment of elements with X-rays.

Question 16

Who discovered atomic number?

Answer 16

Henry Moseley

Question 17

Who discovered the neutral particle of atoms?

Answer 17

James Chadwick

Question 18

Scientists who did work with quantum or theoretical physics?

Answer 18

Neil Bohr
De Broglie
Max Planck

Question 19

Describe quantization of electron energy

Answer 19

The energy of an electron is not continuous but quantized. Each electron has certain energy and sub-energy levels available to it, which determine its location and orientation in space

Question 20

The orientation and location of an electron in extranuclear space will change when…

Answer 20

The right amount of energy is gained or lost

Question 21

What is an orbital?

Answer 21

A region in space in which the probability of finding an electron is maximum, based on its wave-particle duality.

Question 22

Each orbital is characterized by its…

Answer 22

…shape and orientation

Question 23

What is the importance of quantum numbers?

Answer 23

They exclusively characterize the energy of each electron and hence, determine its location and orientation in the extra nuclear space

Question 24

What are the quantum numbers?

Answer 24

Principal quantum number
Azimuthal quantum number
Magnetic quantum number
Spin quantum number

Question 25

The Principal quantum number describes...

Answer 25

The orbit or shell or main energy level in which the electron is relative to the nucleus.

Question 26

The Azimuthal quantum number describes...

Answer 26

The shape of the orbital

Question 27

Magnetic quantum number describes...

Answer 27

...the orientation of the orbital in space

Question 28

The Spin quantum number describes...

Answer 28

The orientation of the electron in an external magnetic field or relative to its paired counterpart

Question 29

Electronic configuration describes...

Answer 29

...the representation of arrangements of electrons distributed among the orbital shells and sub shells

Question 30

How many types of orbitals are there?

Answer 30

4 - s, p, d, f

Question 31

Basic rule for writing electronic configuration

Answer 31

Orbitals are filled in a way to minimize energy so the principal energy level is filled in order of increasing energy (as electrons go farther from the nucleus)

Question 32

What is Pauli’s exclusion principle?

Answer 32

No two electrons can have the same four quantum numbers. The first 3 may be the same but the last is always different. Also, 2 or more identical fermions cannot occupy the same quantum states with a quantum system simultaneously

Question 33

Which rule has it that two electrons that are present in the same orbital must have opposite spins?

Answer 33

Pauli’s exclusion principle

Question 34

What is Hund’s rule in full?

Answer 34

Hund’s rule of maximum multiplicity

Question 35

State Hund’s rule

Answer 35

For a given electronic configuration, the lowest energy term is the one with the greatest value of spin multiplicity.

Question 36

Explain Hund’s rule

Answer 36

If two or more orbitals of equal energy (degenerate orbitals) are available, electrons will occupy them singly before filling them in pairs.

Question 37

What is Aufbau’s principle?

Answer 37

In the ground state of an atom/ion, electrons fill atomic orbitals of the lowest available energy level before occupying higher ones, meaning that there is a buildup.

Question 38

An atom with some unpaired electrons is referred to as...

Answer 38

Paramagnetic

Question 39

An atom with all paired electrons is referred to as...

Answer 39

Diamagnetic

Question 40

Expected and observed configurations of electrons occurs because...

Answer 40

Electrons arrange themselves in such a way as to achieve better stability, irrespective of rules. Completely filled and half-filled shells are more stable so atoms go for that.