Atomic Orbitals, Electronic Configuration And The Periodic Table Flashcards
Do electrons also have dual nature?
Yes
What are stationary/standing waves
Waves that vibrate in time but do not move in space.
What are orbitals?
Different sizes and shapes of standing waves possible around the nucleus. They can hold a maximum of two electrons
The principle quantum number (n)
Indicates the main energy level for an electron and is related to the size of the orbital.
Angular momentum quantum number (l)
Determines the shape of the subshell and can have values from zero to n-1
Magnetic quantum number (ml)
Determines the orientation of the orbital and can have values between -l and +l
Spin magnetic quantum number (ms)
Determines the direction of spin and can have values of +1/2 and -1/2
Aufbau principle
Electrons fill orbitals in order of increasing energy
Hund’s rule
When degenerate orbitals are available, electrons fill each singly, keeping their spins parallel before spin pairing starts
Pauli exclusion principle
No two electrons in one atom can have the same set of four quantum numbers, therefore, no orbital can hold more than two electrons and these two electrons must have opposite spins
When are orbitals degenerate
In an isolated atom the orbitals within each subshell are degenerate
How is the periodic table divided into four blocks?
S,p,d,f corresponding to the outer electronic configurations of the elements within these blocks.
How can we explain variation in the first, second and subsequent ionisation energies with increasing atomic number for the first 36 elements?
This can be explained in terms of relative stability of different subshell electronic configurations.
What has a special stability?
Half-filled and full sub shells. The more stable the electronic configuration, the higher the ionisation energy.
VSEPR (valence shell electron pair repulsion) theory
Can be used to predict the shapes of molecules and polyatomic ions.
