Question

Atomic number of an element is $42$. Find out the number of electrons present in the valence shell.

Answer 1

1. The valence shell of an atom is the outermost orbital shell of the atom.
2. The element molybdenum has the atomic number $42$ and the electrical configuration $\left[Kr\right]5s^{1}4d^5$.. (Because half-filled and fulfilled orbitals are more stable, 5s contain just one electron whereas 4d has five electrons.)
3. We'll now count how many electrons are at the highest energy level (the valence shell).
4. The 5s subshell has one valence electron and is the highest energy level here.
5. As a result, the number of electrons in the valence shell of an element with an atomic number of 42 equals one electron.