What is an easy formula to remember a shell's capacity in an atom?

The formula that represents an atom's shell capacity is essential for understanding the configuration of electrons within atoms. The correct answer, 2n², indicates that the number of electrons that can occupy a shell is determined by the principle quantum number 'n.'

Here, 'n' denotes the shell level: for the first shell (n=1), the maximum number of electrons is 2(1²) = 2; for the second shell (n=2), it becomes 2(2²) = 8; for the third shell (n=3), it's 2(3²) = 18, and so on. This formula effectively captures the relationship between the energy levels of shells and their capacity to hold electrons, making it a foundational tool for studying atomic structure.

This understanding is crucial for moving beyond just memorizing electron configurations to grasping how elements interact, bond, and form compounds in chemistry.