why is chlorine gas green coloured but y is cl anion non coloured
 

Asked by arghyanathvms | 30th Mar, 2017, 03:15: AM

Expert Answer:

Chlorine gas is green. This is because,
 

In the periodic table, the halogen family are coloured elements. As they get heavier the colour gets darker.

Thus,

Fluorine yellow
Chlorine green
Bromine brown
Iodine purple
Astatine black

The reason is that, the lighter fluorine has more tightly bound outer electrons and absorbs higher energy ultraviolet light.

The yellow you see is the light that has not been absorbed. 

As you get bigger atoms the electrons are more shielded from the nucleus and they are less tightly bound.
 

They absorb longer wavelengths and as the absorption band shifts down into the visible region like a rainbow, in the direction blue to red, the light colours become progressively more absorbed. 

Hence chlorine gas is green in colour.
 
In chloride ion, all the valence electrons are paired in p orbital.

Answered by Prachi Sawant | 31st Mar, 2017, 11:31: AM