To form an ion, how many electrons would carbon need to gain or lose?

To understand how carbon forms an ion and the number of electrons it needs to gain or lose, it's essential to look at its atomic structure. Carbon has an atomic number of 6, which means it has 6 protons and, typically, 6 electrons. Its electron configuration is 1s² 2s² 2p², which reveals that it has four outer electrons (two in the 2s subshell and two in the 2p subshell).

Carbon can achieve a full outer electron shell, resembling the stable configuration of noble gases, by either gaining or losing electrons.

If carbon were to gain four electrons, it would have a total of eight electrons, filling its outer shell and becoming negatively charged (an anion). Conversely, if carbon were to lose four electrons, it would have no outer shell electrons left, resulting in a positively charged ion (a cation).

Therefore, to form a complete outer shell corresponding to a stable ion state, carbon needs to gain or lose four electrons, making the formation of the ion critically linked to its ability to reach this stable electronic configuration.