name the following 

i.a poly atomic gas

ii. a monovalent element

iii. an element with duplet

iv. a solid non metal

v . an element whichn give harmful radiations

i. a polyatomic gas = CO₂

ii. a monovalent element = chlorine (Cl^1-)

iii. an element with duplet = hydrogen and helium

iv. a solid non-metal = iodine

v. an element which give harmful radiations = radium