Question

give reason for the following: (i) 40/18 Ar and 40/20 ca are called isobars. (ii)' He' and 'Ne' have a zero valency. (iii) an atom is neutral . (iv) neutral is positively charged .(v) isotopes have similar chemical properties.

Answer 1

I) because Ar and ca having same mass no. but different atomic no.
2) they have stable electronic configuration there outermost shell are filled
3)because there overall charge is zero