Boron has two isotopes and . If atomic weight of Boron is 10.81 then ratio of to in nature will be:
1. 15 : 16
2. 19: 81
3. 81 : 19
4. 20: 53
The volume occupied by an atom is greater than the volume of the nucleus by a factor of about:
1. \(10\)
2. \(10^5\)
3. \(10^{10}\)
4. \(10^{15}\)