$1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}4{\mathrm{s}}^1$ is the electronic configuration of

There is total 19 electrons are present in an element with given electronic configuration. so the atomic number of an element is 19. Therefore, the symbol of the element is ‘K’.