Atomic Structure Flashcards
When did John Dalton develop his atomic theory?
1808
Michael Faraday and Davy’s work
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.
JJ Thomson’s work
He confirmed the presence of negatively charged components of matter in his popular discharge tube experiments
What did Thomson describe his negatively charged components of matter as?
Cathode rays
The charge to mass ratio of cathode rays are constant. True or false?
True
What is the value of the charge-to-mass ratio of cathode rays?
1.76 x 10^11 C/kg
Who carried out the oil drop experiment?
Robert Millikan
Who calculated the exact mass on an electron?
Robert Millikan
How did Millikan calculate the exact mass on an electron?
He used the charge-mass constant
What is the charge on an electron?
1.6 x 10^-19
What is the mass of an electron?
9.11 x 10^-31 kg
What did Ernest Rutherford describe?
Protons
Who developed the planetary model of the atom?
Ernest Rutherford
Describe Rutherford’s experiment
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
What did Henry Moseley do?
…He determined the number of protons in the nucleus of an atom from his work involving the bombardment of elements with X-rays.
Who discovered atomic number?
Henry Moseley
Who discovered the neutral particle of atoms?
James Chadwick
Scientists who did work with quantum or theoretical physics?
Neil Bohr
De Broglie
Max Planck
Describe quantization of electron energy
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
The orientation and location of an electron in extranuclear space will change when…
The right amount of energy is gained or lost
What is an orbital?
A region in space in which the probability of finding an electron is maximum, based on its wave-particle duality.
Each orbital is characterized by its…
…shape and orientation
What is the importance of quantum numbers?
They exclusively characterize the energy of each electron and hence, determine its location and orientation in the extra nuclear space
What are the quantum numbers?
Principal quantum number
Azimuthal quantum number
Magnetic quantum number
Spin quantum number
The Principal quantum number describes…
The orbit or shell or main energy level in which the electron is relative to the nucleus.
The Azimuthal quantum number describes…
The shape of the orbital
Magnetic quantum number describes…
…the orientation of the orbital in space
The Spin quantum number describes…
The orientation of the electron in an external magnetic field or relative to its paired counterpart
Electronic configuration describes…
…the representation of arrangements of electrons distributed among the orbital shells and sub shells
How many types of orbitals are there?
4 - s, p, d, f
Basic rule for writing electronic configuration
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)
What is Pauli’s exclusion principle?
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
Which rule has it that two electrons that are present in the same orbital must have opposite spins?
Pauli’s exclusion principle
What is Hund’s rule in full?
Hund’s rule of maximum multiplicity
State Hund’s rule
For a given electronic configuration, the lowest energy term is the one with the greatest value of spin multiplicity.
Explain Hund’s rule
If two or more orbitals of equal energy (degenerate orbitals) are available, electrons will occupy them singly before filling them in pairs.
What is Aufbau’s principle?
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.
An atom with some unpaired electrons is referred to as…
Paramagnetic
An atom with all paired electrons is referred to as…
Diamagnetic
Expected and observed configurations of electrons occurs because…
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.
