Atomic Structure

Atomic Structure

1. ·

   • Principal Quantum Number (n): n = 1, 2, 3, …, ∞
   • Angular Momentum (Secondary, Azimunthal) Quantum Number (l): l = 0, ..., n-1.
   • Magnetic Quantum Number (ml): ml = -l, ..., 0, ..., +l.
   • The number of orbitals in a shell is the square of the principal quantum number

2. Queries: quantum shell is electron shell?

3. Ionisation Energy

   • Across the period, the nuclear charge of the elements increases. The shielding effect remains almost constant. Thus, the effective nuclear charge increases with the valence electron pulled closer to the nucleus. Larger amount of energy is needed to remove the electron, thus increasing ionization energy
   • Electronic configuration of B: 1s2 2s2 2p1 . Removal of the valence electron from B comes from the 3p orbital, which is of higher energy level than the 3s orbital for Be. Thus, amount of energy required to remove the valence electron for B is lesser with lower ionization energy.
   • Down the group, the nuclear charge increases. The shielding effect outweighs the effect of increasing nuclear charge, thus effective nuclear charge decreases. The valence electron experiences a weaker force of attraction to the nucleus. Smaller amount of energy is required to remove the electron, thus ionization energy decreases.
   • Charge of ion increases, successive IE increases
   • nuclear charge, shielding effect, effective nuclear charge

4. Electron Configuration (Special Cases): Chromium [Ar]3d54s1, Copper [Ar] 3d10 4s1

5. mono di tri tetra penta hexa hepta nona deca

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