Which among the following represents a set of isotopes? Atomic nuclei that contain: I) 5 protons and 5 neutrons
II) 5 protons and 6 neutrons
III) 6 protons and 6 neutrons
IV) 6 protons and 5 neutrons
V) 5 protons and 7 neutrons

Enzyme make a hormone as a catalyst

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.

(no3)⁻n has oxidation number x,o has oxidation number -2.(x*1 -2*3) charge of the nitrate ion, and we know that charge of the nitrate ion =-1.so,(x*1 -2*3) =-1x-6=-1x=+5answer a. +5.