Comprehensive BSc First-Year Chemistry Notes

BSc First-Year Chemistry Notes



1. INORGANIC CHEMISTRY

(A) Atomic Structure

1. Bohr's Model

- Electrons revolve around the nucleus in fixed orbits.

- Energy levels (shells) are quantized:

E_n = -13.6 / n^2 eV



2. Quantum Numbers

- Principal Quantum Number (n) - Represents the shell.

- Azimuthal Quantum Number (l) - Represents subshell (s, p, d, f).

- Magnetic Quantum Number (m) - Represents orbital orientation.

- Spin Quantum Number (s) - Represents electron spin (+1/2 or -1/2).



(B) Periodic Table and Periodicity

1. Atomic Radius - Decreases across a period; increases down a group.

2. Ionization Energy - Increases across a period; decreases down a group.

3. Electronegativity - Increases across a period; decreases down a group.



(C) Chemical Bonding

1. Ionic Bond - Transfer of electrons (Example: NaCl).

2. Covalent Bond - Sharing of electrons (Example: H2, O2, CH4).

3. Coordinate Bond - One atom donates a pair of electrons (Example: NH3 -> BF3).



(D) Molecular Orbital Theory

- Bonding orbital -> Lower energy -> Stability.