How many electrons are present in the M-shell of an atom of an element with atomic number 24.

Atomic number 24 is chromium

Electronic configuration -$1{\mathrm{S}}^{2}2{\mathrm{S}}^{2}2{\mathrm{P}}^{6}3{\mathrm{S}}^{2}3{\mathrm{P}}^{6}4{\mathrm{S}}^{1}3{\mathrm{d}}^5$

M-shell means $3^{\mathrm{rd}}$ Shell -$3{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{d}}^5$

∴  Number of electrons in M-Shell-13