The maximum number of electrons that can be accommodated in the innermost electron shell, also known as the first shell or K-shell, is 2. This shell is closest to the nucleus and has the lowest energy level. According to the Aufbau principle and the rules of electron configuration, the first shell can hold a maximum of 2 electrons. The second shell, or L-shell, can hold a maximum of 8 electrons, while subsequent shells can accommodate even larger numbers as you move further away from the nucleus.