Une is a synthetic chemical element with symbol Mt (Meitnerium) and its atomic number is 109.<br/><br/> Because in one, U= un, i.e. l,n= nil, i.e. 0
e=enn , i. e. 9
Its come under d - block trans actinide elements. It is an extremely radioactive synthetic element which is not forund in nature and synthesised in laboratory.