Question

why fluorine does not form coloured compound while Iodine does?​

Answer 1

Answer:

Colors of substances result when the energy difference between an occupied orbital and an unoccupied (or incompletely occupied) orbital matches that of some wavelength of visible light, which can then be absorbed. The d-orbitals of transition metals often fit this description, which is why transition metal compounds are often colored, but it doesn’t have to be due to d-orbitals.

When halogen molecules form, the valence atomic orbitals interact to form a total of 8 molecular orbitals (MOs). There are a total of 14 valence electrons from the 2 halogen atoms, which means that 7 of the molecular orbitals are filled, and the highest-energy one remains empty. The difference in energy between it and the occupied next-highest orbitals (there are two, of the same energy) falls in the region of visible light: violet for fluorine, and decreasing in energy as you move down the column of the periodic table. (I don’t think anyone has ever managed to get a visible quantity of astatine; one could presumably calculate a predicted peak absorption wavelength, but I don’t know what it is.)

For other diatomic elements, like H₂ and O₂, the corresponding differences in orbital energy are in the ultraviolet range, and so we don’t see any color (although liquid O₂ is bluish…)

Explanation:

Answer 2

Answer:

Explanation:)Fluorine has no d orbitals

ii)Iodine is covalent in nature and therefore, it does not dissolve in water which polar. In KI solution, iodine reacts to form KI3 which is ionic in nature. ∴it becomes soluble in water.

iii) Because of increase in atomic sizes and hence increases in van der Waal’s forces.

iv)Ammonia is a good complexing agent because of the presence of lone pair of electron on nitrogen. This lone pair of electron can easily be donated to electron deficient compounds forming complexes

v)Nitric oxide (NO) is a clourless gas, when released in air, it immediately changes to nitrogen dioxide(NO2) which has a brown colour

2NO(g)+O2(g)→2NO2(g)

It is colourless Brown