Class 11 Chemistry Structure of Atom | Pauli’s exclusion Principle |

__Pauli’s exclusion Principle__

According to it: “no two electrons can have the same set of all four quantum numbers.”

Or, it states that an orbital can have maximum of two electrons and that must be of opposite spin. Due to this, it was concluded that an orbital can have maximum of two electrons which can have all 3-quantum number same but the spin will be definitely different.

__Shapes of atomic orbitals:__

**s –orbital**

Its shape is spherical.For 1s the probability of finding electron is maximum near nucleus and it decreases as we move away from nucleus.

For 2s: Again, probability of finding electron is maximum near nucleus and decrease as the distance increase. But it has one ring in it, where probability of finding electron is zero that is a nodal plane or a node.

The shape of 2s differs from 1s as it has one node and 1s has no node. Similarly, in 3s there are two nodes.

The different s orbitals differ from each other in number of nodes, size and energy.

**Shape of p orbital**

Its shape is dumb-bell. It is found that probability of finding electron is maximum in both the lobes. There is a plane passing through nucleus where probability of finding the electron is almost zero. That is nodal plane.

There are 3 sub-shells: p_{x}, p_{y} and p_{z.}

It is directional in nature.All the 3 p orbitals are degenerate that is have same energy.

**Shape of d orbital**:

It has 5 subshells:d_{xy},d_{yz},d_{zx},d_{x2-y2} and dz^{2}

There shapes are given as shown:

The shape of dz^{2} is called as doughnut shape or baby soother type shape.

Number of nodes in any orbital can be calculated by: (n-l-1).

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