Isotopes are the atoms of same element, they have same atomic number but different mass number. Isotopes have different number of neutrons in their nucleus. If an element exists in two isotopes having atomic masses .a. and .b. in the ratio m : n, then average atomic mass will be mxa+nxb/m+n Different isotopes of same element have same position in the periodic table. The elements which have single isotope are called monoistropic elements. Greater is the percentage composition of an isotope, more will be its abundance in nature. Atomic mass of boron is 10.81. It has two isotopes namely ""_(5)B^(11)and""_(5)B^(x) with their relative abundance of 80% and 20% respectively. The value of x is

Isotopes are the atoms of same element, they have same atomic number b

1.	Isotopes are the atoms of same element, they have same atomic number but different mass number. Isotopes have different number of neutrons in their nucleus. If an element exists in two isotopes having atomic masses .a. and .b. in the ratio m : n, then average atomic mass will be mxa+nxb/m+n Different isotopes of same element have same position in the periodic table. The elements which have single isotope are called monoistropic elements. Greater is the percentage composition of an isotope, more will be its abundance in nature. Atomic mass of boron is 10.81. It has two isotopes namely ""_(5)B^(11)and""_(5)B^(x) with their relative abundance of 80% and 20% respectively. The value of x is
Answer» `10.05` 10 `10.01` `10.02` SOLUTION :`10.81=0.8xx11+0.2xx X` `IMPLIES x=(10.81-8.8)/(0.2)=10.05`