If the electronic configuration of an element is 1s22s22p63s23p63d24s2, the four electrons involved in chemical bond formation will be

The given electronic configuration shows that the element is titanium (Z = 22).It belongs to d-block of the periodic table. In transition elements, i.e. d-block elements, electrons of ns and (n - l) d- subshell take part in bond formation.Hence, 3d2,4s2 contain 4 electrons which will be involved in chemical bond formation.