Which of the following metals has the highest melting point?

The correct answer is Option (2) → W

All four metals belong to the 5d series (Ta, W, Re, Os, in order of atomic number). On the 5d curve of Fig. 4.1 the melting point rises from Hf to a peak at W (tungsten), then falls through Re and Os. So W has the highest melting point of the four, with Re, Ta and Os all lower.

NCERT (2026-27 edition):
4.3.1 Physical Properties – “… Their melting and boiling points are high. Fig. 4.1 depicts the melting points of transition metals belonging to 3d, 4d and 5d series. The high melting points of these metals are attributed to the involvement of greater number of electrons from (n-1)d in addition to the ns electrons in the interatomic metallic bonding.”

Fig. 4.1: Trends in melting points of transition elements