Answer: b) Mass number is 9.
The atomic symbol for beryllium 9/4 be indicates that the mass number is 9.
Explanation:
Beryllium metal, Be was placed in second group and second period of periodic table. It occur as solid at 20°C. Its atomic number is 4 and the mass number is 9.
Atomic number, Z = number of proton or number of electrons in the atom.
Mass number = Atomic no + number of neutrons in the atomic nucleus.
So the atomic symbol for beryllium is indicated as mass number of 9.
