Which atom is likely to be more chemically reactive, an atom with a partly filled energy level or an atom with all energy levels completely filled? explain?

It is more reactive the atom with a partly filled energy level because is less stable than the other case. Stability is inversely proportional to reactivity.

The correct option is an atom with a partly filled energy level

Explanation:

An atom with a partially filled energy level means the atom has a partially filled outermost shell which in turn means the atom as valence electrons. The presence of valence electrons in atoms makes them undergo chemical bonding with other atoms of the same/different elements (during chemical reactions).

Atoms with completely filled energy levels (such as the noble gases) have a completely filled outermost shell and hence do not have valence electrons which can take part in bond formation during chemical reactions and hence these group of atoms have low chemical reactivity.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.