Question

4.6 x 10^23 atoms of an element weigh 13.8gm

Answer 1

mass of 4.6×10^22 atoms =13.8

mass of one atom =13.8/4.6×10^23gm

atomic mass of an element=one mole of element

=6.022×10^23 * 13.8/4.6×10^23
=18.066
the element is fluorine.

Answer 2

4.6×10^23 atoms of an element weigh 13.8gm

1atom will weigh=13.8/4.6×10^23

atomic mass of an element=1mole of an element

so mass of the element=6.023×10^23×13.8/4.6×10^23