In a certain code language, G is written as S, L as A, A as O, O as N, N as E, E as G, H as L and S as H. How will HALOGENS be written in that code?

LOANSGEH

Given; In a certain code language, G is written as S, L as A, A as O, O as N, N as E, E as G, H as L and S as H. 

So,

Words  G  L  A  O  N  E  H  S

Codes  S  A  O  N  E  G  L  H

Thus, as per the codes;

HALOGENS is written as LOANSGEH