Question

state why the valency of the metal potassium is +1 and of the non metal chlorine is -1

Answer 1

This is because the radical for potassium is 1 because it has only one molecule. So in the chlorine

Answer 2

because k metal have atomic number 19 ...E.C is 2,8,8,1 one electron easily lose ..but in Cl atom at. number is 17...E.c is 2,8,7 one electron easily gain....That's why k metal have +1 valency if a atom gain one electron then it have -1 valency if an atom lose one electron then it have +1 valecncy ...That is why Cl have -1 electron.....