_ grade XI_

• Intermolecular force
1. Van Der Waals Forces
a. London Force = Disperse Forces
Dipoles force is press together inter-molecule force in non polar substance. London force is a relatively weak force.
b. Dipoles Attraction Force
Dipoles attraction force is inter-molecule force in non polar substance. It is stronger than London force.
c. Superficially Dipoles Attraction Force
This attraction force is an attraction force between polar and non polar molecule. It is electrostatic attraction force between dipole and temporary dipole.
2. Hydrogen Bonding
It is an attraction force between hydrogen atom bonded to an atom with strongly electronegative, such as fluor (F), oxygen (O), and nitrogen (N) from the other molecule surrounding it. Hydrogen bonding is stronger than Van Der Waals forces.


Electron domain theory is perfecting of VSEPR theory. Domain electron means position of electron or presence of electron area.
Basic principle and electron domain theory:
1. Inter-electron domain in outer shell of centre
2. Inter NBEP refusal > refusal between NBEP and BEP > Inter BEP refusal
3. Shape of molecule only determined by BEP
Predicting the shape of molecules:
 Centre atom represented as A symbol
 Each bonding electron domain represented as X, and
 Each free electron domain represented as E
1. Biner compound with single bonding:

Where:
EV = amount of centre atom valence electron
X = amount of bonding electron domain (= amount of atom bonded to the centre atom)
E = amount of free electron domain
2. Biner compound with double bonding or covalent coordinate bonding:

Where:
X’ = amount of electron used by centre atom
Polar and non polar molecules, a molecule will be polar if it full these conditions:
1. Molecule bonding is polar
2. The shape of molecule is not symmethrical, so that the centre of positive charge and centre of negative charge don’t press together.
Hybridization is a process of orbital from different energy level dissolving to be orbital in the same level.

• The Bohr Atomic theory and quantum mechanic
The Bohr model consists of four principles:
1. Electrons assume only certain orbits around the nucleus. These orbits are stable and called "stationary" orbits.
2. Each orbit has an energy associated with it. For example the orbit closest to the nucleus has an energy E1, the next closest E2 and so on.
3. Light is emitted when an electron jumps from a higher orbit to a lower orbit and absorbed when it jumps from a lower to higher orbit.
4. The energy and frequency of light emitted or absorbed is given by the difference between the two orbit energies, e.g.,
E(light) = Ef - Ein = E(light)/h
h = Planck's constant = 6.627x10-34 Js
where "f" and "in" represent as final and initial orbits.
The displacement of electrons is an atom from nth shell to the infinity shell will cause the atom to be charged (ionized) and the amount of energy required to release electrons from the nth shell to the infinity shell is called the ionization energy.
Based on Schrodinger’s atomic model, the quantization of angular momentum of electron as it has been proposed by Bohr can occur because the electron wave forms a stationary wave. In this case, the atomic model based on wave characteristics of electron describe by using this Schrodinger’s wave function is called the atomic model of quantum mechanics or atomic model of wave mechanics.


• Quantum number and orbital form.
Bilangan kuantum digunakan untuk menyatakan orbital atom.
Jenis Nilai Fungsi
Utama (n) 1, 2, 3, dst sesuai kulit K, L, M, dst menentukan tingkat energi orbital atau kulit atom
Azimut (l) l = 0 sampai (n-1) menyatakan bentuk orbital (subkulit)
Magnetik (m) m = - l, 0, hingga +l menyatakan orientasi orbital dalam ruang (jumlah orbital dalam subkulit)
Spin (s) s = +1/2 dan s = -1/2 menyatakan arah rotasi elektron
Jumlah maksimum elektron pada kulit ke-n = 2n2

• The electrons configuration (Aufbau principle, Hund rule and Pauli prohibition rule) and its relation to the periodic system.
Rules to write the configuration of electron:
1. Aufbau :
Principle Filling up of orbital start from lower energy level to the higher energy level
2. Hunds Rule : Filling up of orbital in the same energy level, initially it will fill the orbital individually with paralel spin, then get in pairs
3. Pauli Exlusion:
Principle In an atom, there is not be allowed two electrons which have same four of quantum number (n, l,m,and s)

Some note about configuration of electron:
1. Stability of d subshell that full filled or half filled.
2. Configuration of ion electron:
Individual ion charged X+, from it neutral atomic configuration by releasing x electron. The releasing electron is valence electron. Individual ion charged X- formed from it neutral atomic by absorbing x electron. Absorbing electron fill the orbital with the lowest energy level that haven’t full yet.

Periodic system and configuration of electron :
 The highest energy level shows the period.
 Valence electron shows the element group.