Final answer:
The second electron shell can hold up to eight electrons, split between one 2s orbital and three 2p orbitals, each capable of holding two electrons.
Step-by-step explanation:
The second electron shell can hold a total of eight electrons. This capacity is due to the shell's subdivision into one spherical 2s orbital and three 2p orbitals, with each capable of containing two electrons. The 2s orbital is filled first, followed by the three 2p orbitals.
According to the Pauli exclusion principle and Hund's rule, each p orbital receives one electron before any of them get a second, ensuring that electrons are distributed evenly. For example, the element lithium (Li) has three electrons, the first two filling the 1s orbital and the third going into the 2s orbital, giving it an electron configuration of 1s²2s¹. Neon (Ne), with ten electrons, completely fills both its 1s and 2nd shell orbitals, making it a noble gas with a stable electron array unlikely to form bonds easily.