The number of electrons in `[._19^40K]^(-1)` is

The atomic number of an element X is 19. The number of electrons in its ion X^(+) will be

The number of electrons plus neutrons in ._(19)^(40)K^(+) is-

The energy of an electron is 4.0 xx10^(-19) J.Express it in eV.

In a pure semiconductor, the number of conduction electrons is 6xx10^(19) per cubic metre. Find the total number of current carriers (electrons and holes) in a same semiconductor of size 1cmxx1cmxx1mm .

" The maximum number of electrons in "K" atom "(Z=19)" with quantum numbers "n=3,m=+1,s=+(1)/(2)" is "

Calculate the number of proton, neutrons and electrons in ._(19)^(39) K .