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 ._(

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 :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.