Electron Configuration - What is it? What are S P D F subshells? How to write configurations

Overview of Electron Configuration Chronological Order

1. Shells

   • Definition: Shells represent the main energy levels around the nucleus where electrons reside.

   • Structure of Shells:

     • There are seven principal shells denoted by numbers 1 through 7.

     • Shells are arranged by periods on the periodic table and are numbered from the nucleus outward.

     • Shell 1 is the smallest and has the least energy, containing hydrogen and helium.

     • As you move to shell 7, the shells increase in size and energy.

2. Subshells

   • Definition: Subshells are subdivisions of shells characterized by specific shapes and energies.

     • Types of Subshells:

       • The four types of subshells are represented by the letters: s, p, d, and f.

         • s subshell: Spherical shape.

         • p subshell: Dumbbell shape.

         • d subshell: Flower shape with more complex geometry.

         • f subshell: Highly complex 3D shape.

   • Relationship with Shells:

     • Each shell contains a specific set of subshells, which vary in number:

       • Shell 1 contains 1s.

       • Shell 2 contains 2s and 2p.

       • Shell 3 contains 3s, 3p, and 3d, etc.

3. Orbitals

   • Definition: Orbitals are regions within subshells where electrons are likely to be found.

   • Structure of Orbitals:

     • Each subshell can contain a specific number of orbitals:

       • s subshell: 1 orbital

       • p subshell: 3 orbitals

       • d subshell: 5 orbitals

       • f subshell: 7 orbitals

     • Maximum number of electrons per orbital is two, corresponding to the spins (upspin and downspin).

4. Analogy of Electron Configuration

   • Apartment Complex Analogy:

     • Floors (Shells): Each floor of an apartment building represents a shell.

     • Apartments (Subshells): Different apartments on the same floor represent subshells.

     • Rooms (Orbitals): The individual rooms in an apartment symbolize orbitals where electrons are found.

   • Example:

     • 4th floor (Shell 4) consists of:

       • 1 S Apartment (1 room)

       • 1 P Apartment (3 rooms)

       • 1 D Apartment (5 rooms)

       • 1 F Apartment (7 rooms)

5. Electron Configuration in the Periodic Table

   • Shell and Subshell Mapping:

     • Shells correlate to periods on the periodic table ascending from 1 to 7.

     • S block: contains elements in Groups 1 and 2, including helium.

     • P block: starts at the edge of boron, includes Groups 13 to 18.

     • D block: corresponds to the transition metals.

     • F block: includes inner transition metals such as lanthanides and actinides.