Which of the following inorganics is known to affect the nervous system adversely?

Copper is known to adversely affect the nervous system due to its role as a neurotoxin in certain cases. Elevated levels of copper in the body can lead to a range of neurological problems, including cognitive deficits, mood disturbances, and coordination issues. This toxicity is often associated with conditions like Wilson's disease, where copper accumulates in the body due to a genetic defect in copper metabolism.

In contrast, while calcium, sodium, and potassium are essential for many bodily functions—including nerve transmission and muscle contraction—excessive levels of these minerals typically do not have the same neurotoxic effects as copper. Instead, they can lead to other health issues, but they are not classified in the same way as copper when considering adverse effects on the nervous system specifically. Understanding the distinct roles that these minerals play can help differentiate their effects, particularly in relation to neurological health.