A monoatomic anion of unit charge contain 45 neutrons and 36 electrons. What is the atomic mass number of element and in which group of periodic table does it lie? Write your answer as 1002 if answer is 10,2.

Explanation

No. Of neutrons of the monoatomic anion = 45
No. of electrons of the monoatomic anion = 36 `:. ` No. of electrons of the monoatomic atom= 36 -1 = 3
`:. ` Atomic number of the atom `(Z= 35)` . Therefore the atom is bromine and it belongs to group 17, i.e., halogen family .
No. of protons = No. of electrons =35
`:. ` Atomic mass = No . of neutrons + No. of protons = 45 + 35 =80