Symbols ._(35)^(79)Br and .^(79)Br can be written whereas symbols ._(79)^(35)Br and ._(35)Br are not acceptable. Answer briefly.

Symbols ._(35)^(79)Br and .^(79)Br can be written whereas symbols ._(7

1.	Symbols ._(35)^(79)Br and .^(79)Br can be written whereas symbols ._(79)^(35)Br and ._(35)Br are not acceptable. Answer briefly.
Answer» Solution :`._(79)^(35)BR` is not acceptable because atomic number should be written as SUBSCRIPT, while mass number should be written as SUPERSCRIPT. `._(35)Br` is not acceptable because atomic number of an element is fixed. HOWEVER, mass number is not fixed as it depends upon the isotope taken. Hence, it is essential to indicate mass number.