the 2s orbital is at a higher energy level
You can tell the difference between 2s sub-shell and 2p sub-shell by checking their energy levels whereby a 2p orbital has a higher energy level compared to a 2s orbital.
You can tell the difference between a 2s sub-shell and 2p sub-shell from their energy levels, because a 2p sub-shell is a higher energy level than a 2s sub-shell.
25 of them
20 of them.
Seven of them.
240 ÷ 2 = 120
Exactly 18 of them
It has 17 of them with a remainder of 1
5,0 moles (NH4)2S contain 60,22140857.10e23 ammonium ions.
150 g x 1 mol/68.154 g = 2.2 moles (2 sig figs)
The compound (NH4)2S is ammonium sulfide.