Answer:

The element with the lowest melting point is Krypton.

Explanation:

Melting point is defined as the temperature at which a solid substance changes into a liquid. The melting point of an element depends on several factors such as the strength of the metallic bond, the crystal structure, and the atomic size.

Krypton is a noble gas with the atomic number 36 and the symbol Kr. It is a non-reactive gas that is present in the Earth's atmosphere and is used in fluorescent lamps and other industrial applications. Krypton has the lowest melting point among the given elements because of the following reasons:

1. Weak van der Waals forces: Krypton is a noble gas that exists as single atoms. The van der Waals forces between krypton atoms are weak, and hence it requires less energy to break these forces and convert the solid into a liquid.

2. Small atomic size: Krypton has a small atomic size compared to the other elements in the list. The small size allows the atoms to pack closely together, resulting in a weaker metallic bond.

3. Simple atomic structure: Krypton has a simple atomic structure with a filled outer electron shell. This structure leads to weak interatomic interactions, resulting in a low melting point.

In summary, Krypton has the lowest melting point among the given elements due to weak van der Waals forces, small atomic size, and a simple atomic structure.