CBSE Class 9 Answered

Heisenberg’s Uncertainty Principle states that it is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of an electron.

The Schrödinger wave equation is written as where H is a mathematical operator called Hamiltonian.

Pauli exclusion principle can also be stated as: “Only two electrons may exist in the same orbital and these electrons must have opposite spin.” This means that the two electrons can have the same value of three quantum numbers n, l and ml, but must have the opposite spin quantum number.