Summary of SPDF orbitals Explained - 4 Quantum Numbers, Electron Configuration, & Orbital Diagrams

Summary of "SPDF orbitals Explained - 4 Quantum Numbers, Electron Configuration, & Orbital Diagrams"

This video provides a detailed explanation of atomic orbitals (s, p, d, f), Quantum Numbers, electron configurations, and Orbital Diagrams, focusing on how electrons are arranged within atoms according to quantum mechanics principles.

Main Ideas and Concepts:

1. Shapes and Sublevels of Orbitals:
   • s orbital: Spherical shape; 1 orbital; holds up to 2 electrons.
   • p orbital: Dumbbell shape; 3 orbitals; holds up to 6 electrons.
   • d orbital: Cloverleaf shape; 5 orbitals; holds up to 10 electrons.
   • f orbital: Complex shape; 7 orbitals; holds up to 14 electrons.
2. Relationship Between Principal Energy Levels (n) and Sublevels:
   • Number of sublevels = principal quantum number (n).
   • For example:
     • n=1 → 1 sublevel (1s)
     • n=2 → 2 sublevels (2s, 2p)
     • n=3 → 3 sublevels (3s, 3p, 3d)
     • n=4 → 4 sublevels (4s, 4p, 4d, 4f)
3. Quantum Numbers:
   • n (Principal quantum number): Energy level.
   • l (Azimuthal quantum number): Sublevel type (s=0, p=1, d=2, f=3).
   • ml (Magnetic quantum number): Orbital within sublevel:
     • s: ml = 0 (1 orbital)
     • p: ml = -1, 0, +1 (3 orbitals)
     • d: ml = -2, -1, 0, +1, +2 (5 orbitals)
     • f: ml = -3 to +3 (7 orbitals)
   • ms (Spin quantum number): Electron spin (+½ or -½).
4. Determining Quantum Numbers for Specific Electrons:
   • Example: For a 3p⁵ electron:
     • n = 3
     • l = 1 (p)
     • ml = 0 (fifth electron in p orbitals)
     • ms = -½ (spin down)
   • Similar examples are given for 4d⁴ and 5f¹³ electrons.
5. Pauli Exclusion Principle:
   • No two electrons can have the same set of four Quantum Numbers.
   • Each electron’s Quantum Numbers uniquely identify it.
6. Electron Configuration:
   • Writing electron configurations involves filling orbitals in order of increasing energy.
   • Example: Phosphorus (15 electrons)
     • 1s² 2s² 2p⁶ 3s² 3p³
   • The sum of exponents equals the total number of electrons.
7. Orbital Diagrams and Electron Filling Rules:
   • Aufbau Principle: Fill orbitals starting from the lowest energy level.
   • Hund’s Rule: When filling degenerate orbitals (orbitals of equal energy), place one electron in each orbital before pairing.
   • Electrons are represented as arrows (up or down) to indicate spin.
   • Degenerate orbitals (like the three p orbitals) have the same energy.

Methodology / Instructions for Finding Quantum Numbers and Writing Electron Configurations:

• To find the four Quantum Numbers for an electron:
  1. Identify the principal energy level (n).
  2. Determine the sublevel type (l) based on the orbital (s=0, p=1, d=2, f=3).
  3. Find the magnetic quantum number (ml) by locating the specific orbital within the sublevel.
  4. Determine the electron spin (ms) based on the electron’s arrow direction (up = +½, down = -½).
• To write Electron Configuration:
  1. Know the total number of electrons (atomic number).
  2. Fill orbitals in order of increasing energy (1s → 2s → 2p → 3s → 3p → 4s → 3d → 4p, etc.).
  3. Use exponents to indicate the number of electrons in each sublevel.
  4. Ensure the sum of electrons matches the atomic number.
• To draw Orbital Diagrams:
  1. Draw boxes or lines representing orbitals.
  2. Fill electrons as arrows, starting with up arrows.
  3. Apply Hund’s Rule for degenerate orbitals by placing one electron per orbital before pairing.
  4. Follow the Aufbau Principle.

Notable Quotes

— 10:41 — « Whenever you're filling electrons in degenerate orbitals you have to fill them one at a time. The word degenerate means that the energy is equal. »

— 11:00 — « These three orbitals have equal energy because they're at the same height, so therefore they are degenerate orbitals because they have the same energy. »

— 11:16 — « According to Aufbau principle we move into 3s not 3p because we have to go in order of increase in energy or increase in potential energy. »

— 11:43 — « Write the electron configuration first then put the arrows in. »

— 11:51 — « I think we covered a lot and I have other videos on quantum numbers so feel free to search YouTube for those and so that's all I got for today that's my two cents. »

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Educational

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