For an element with atomic number 35, which one of the following will be the correct number of electrons in its valence shell based on Bohr’s model of an atom?
1
3
5
7
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC NDA-1 – 2022
– The maximum number of electrons a shell can hold is generally given by 2n², where n is the shell number (n=1 for K, n=2 for L, etc.).
– For atomic number 35 (Bromine), we fill the shells sequentially:
– K shell (n=1): 2 electrons (capacity 2)
– L shell (n=2): 8 electrons (capacity 8)
– M shell (n=3): 18 electrons (capacity 18)
– N shell (n=4): The remaining electrons: 35 – (2 + 8 + 18) = 35 – 28 = 7 electrons.
– The outermost shell is the valence shell, which is the N shell in this case.
– The number of electrons in the valence shell is 7.