Why do some elements react vigorously while others are inert?

Why do some elements be monoatomic?

Why do some metals not get rusted ?

Why are some elements chemically inert?

Why do some metals replace the other metals from solution ?

Why are the elements of zero group inert?

Why do some elements exist as molecules and some as atoms?

Why do elements show diagonal relationship ?

(A) Aqueous fluoride on electrolysis at inertanode liberates oxygen (R ) Fluorine reacts vigorously with water to liberate oxygen

Why do some atoms combine while others do not?