Question

1 helium atom an electronic mass of 4u and two protons in to nuscles. jai many neutrons dose it have?
2 the atomic mass of an element X is 16.24. what are the percentage of isotopes of 'X' having atomic no. 8 and Mass no. 16 and 18.

Answer 1

(1) 2 neutrons helium have
(2) X is oxygen