Atomic Structure-Key Points

Atomic Structure – Key Points

1. Aufbau Principle: Electrons fill sub-levels in order of increasing energy: 1s → 2s → 2p → 3s, etc.
2. Azimuthal Quantum Number: Defines the shape of an orbital (s, p, d, f).
3. Balmer Series: Lines in the visible region formed when an electron jumps to the 2nd orbit.
4. Bracket Series: Lines in the infrared region when electrons jump to the 4th orbit.
5. Cathode Rays: Negatively charged particles emitted from the cathode in low-pressure gas.
6. Discharge Tube: A tube with low-pressure gas and electrodes for electric current to pass through.
7. Heisenberg’s Uncertainty Principle: It’s impossible to know both position and momentum of an electron simultaneously.
8. Hund’s Rule: Electrons occupy separate degenerate orbitals with the same spin before pairing.
9. Lyman Series: Ultraviolet lines when electrons fall to the 1st orbit.
10. Magnetic Quantum Number: Describes the orientation of an orbital in a magnetic field.
11. Orbit: A fixed path around the nucleus where an electron revolves.
12. Orbital: A region of high probability where an electron can be found.
13. Paschen Series: Infrared lines formed when electrons jump to the 3rd orbit.
14. Pauli’s Exclusion Principle: No two electrons in the same orbital can have the same four quantum numbers.
15. Pfund Series: Infrared lines from transitions to the 5th orbit.
16. Positive (Canal) Rays: Positively charged rays traveling opposite to cathode rays in a discharge tube.
17. Principal Quantum Number: Represents the main energy level or shell (symbol: n).
18. Quantum Numbers: A set of four numbers that describe an electron’s position and behavior.
19. Sigma Bond: A bond formed by the head-on overlap of orbitals.
20. Spectrum: A band of colors formed when white light is dispersed through a prism.

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