Anuska Bashyal

These models of atom are based on the wave theory and quantum theory respectively.

The quantum mechanical modeldescribes the probable location of electrons in atoms by describing: Principal energy level, energy sublevel, orbital(in each sub-level), spin.

Wave mechanical model isa theory, which states that the electrons have dual nature and are similar to the wave of energy as well as particles. It is also known as quantum mechanical theory.

a. Hund’srule of maximum multiplicity

Hund proposed a rule of filling of de-generate orbitals (having equivalent energy) with electrons known as Hund's rule of maximum multiplicity.

It states:
In the orbitals of same sub-energy level (sub-orbitals), electrons are filled single first (in the same spin) before filling up fully in pair.
The electrons prefer to occupy separate orbitals rather than getting paired in the same orbital.

b. Pauli's Exclusion principle:

Pauli put forward a principle that...

The are main postulates ofDalton’s atomic theory are:

1. All matters are composed of extremely small, and discrete particles called atoms.

2. Atom is indestructible/ indivisible and do not undergo any division during a chemical reaction.
(principle of indestructability of matter)

3. Atoms of same elements are always identical in shape, size and mass and differ from atoms of other elements in the same.

4. Atoms always combine in simple whole number ratio to form a molecule (then called as compound...

During theα-scattering experiment conducted by Rutherford, only very few, almost 1 in 20,000-100,000 particles bounced back.

Hence, we can conclude from this that, the atom has positively charged particles that deflected the +veα-particles, but that positive charge is concentrated in a very very small area compared to the atom itself, such that, it completely deflects the very few particles.