In case of metals, as atomic size increases, boiling point;

Explanation

In metals, as the atomic size increases, the boiling point generally decreases. This is because larger atoms have weaker metallic bonds and weaker interatomic forces compared to smaller atoms. The distance between metal ions increases with larger atomic size, leading to a reduction in the strength of metallic bonds. Consequently, less energy is required to overcome these bonds, resulting in a lower boiling point. However, exceptions to this trend can occur based on other factors, such as electron configuration or additional intermolecular forces that might be present in certain metals. Option A is incorrect because an increase in atomic size does not strengthen metallic bonds. Option C is incorrect as the boiling point is not constant; it decreases with increasing atomic size. Option D is incorrect as the question specifically asks about the relationship between atomic size and boiling point.