So whenever you need to find valence electron look at Group Number and you can find it, Example barium it’s on group 2 it’s means it have 2 valence electrons. let’s look for nitrogen group 5A that means it have 5 valence eletrons. hope it’s help. Let me know if you have any chemistry related questions
The energy of an electron in a hydrogen atom is: <span>E= (-2.179 x 10 ^-18 J)(1/n^2)
</span>where n is the principle energy level of the electron. <span> E= (-2.179 x 10 ^-18 J)(1/4) </span><span>E= -2.179 x 10 ^-18 J </span>E = -5.4 <span>x 10 ^-19 J</span>
