What noble-gas configurations and charge are the following elements likely to attain in reactions in which they form ions? (a) N (c) S (d) Br

Noble gas configuration refers to the electron arrangement of noble gases, which have full outer electron shells, making them stable and unreactive. Elements tend to achieve this configuration by gaining, losing, or sharing electrons during chemical reactions. For example, sulfur (S) can gain two electrons to achieve the electron configuration of argon, a noble gas.

Ion formation occurs when atoms gain or lose electrons to achieve a more stable electronic configuration. Cations are positively charged ions formed by losing electrons, while anions are negatively charged ions formed by gaining electrons. In the case of sulfur, it typically forms an anion (S²⁻) by gaining two electrons to reach a stable noble gas configuration.

The charge of an ion is determined by the difference between the number of protons and electrons in an atom. A neutral atom has equal numbers of protons and electrons, but when it gains or loses electrons, it becomes charged. For sulfur, when it gains two electrons to form S²⁻, it has a net charge of -2, indicating it has two more electrons than protons.