Teaching BPSC बिहार मध्य विद्यालय (6 to 8) शिक्षक भर्ती 4.0 Mock Test General Science Chemistry Basic Concepts of Chemistry
The number of electrons in the valence shell is equal to its _______.
1
Mass number
2
Periodic number
3
Group number
4
More than one of the above
5
None of the above