We have given,

Weight of element M = 35.3g

Weight of compound M₃N₂ = 43.5g

3M + N2 → M₃N₂ (balance equation)

From above balance equation, use can clearly see that 3 mole of element M react with one mole of Nitrogen to form one mole M₃N₂.

Let say. molar mass of element M = x g.

∴ Number of moles of element M = \(\frac {35.3}{x}\)mole and 

Number of moles of M₃N₂ =  \(\frac {43.5}{28 + 3x}\) mole.

∴ 3 mole of element produce = 1 mole M₃N₂

∴ 1 mole of element M produce = \(\frac 13\) mole of M₃N₂

∴ \(\frac {35.3}{x}\) mole of element M produce = \(\frac {35.3}{3x}\) mole of  M₃N₂ 

but \(\frac {43.5}{28 + 3x}\) mole of M₃N₂ formed

Therefore - \(\frac {43.5}{28 + 3x}\) = \(\frac {35.3}{3x}\)

= 130.5x = 988.4 + 105.9 x

= 24.6x = 988.4

x = 40.18g.

i) Hence, the molar mass of element M will be 40.18g

ii) We know that, change on Nitrogen is -3.

∴ Oxidation state of M will be

= Let say - M has oxidation state  y then,

3y + 2 (-3) = 0

= 3y = 6

= y = +2

it means element has oxidation state (valency) +2 and molar mass 40.17g.

We know that Ca has valency +2 and it has molar mass approx 40.078

Therefor compound will be Ca₃N₂ 

And the name of compound is Calcium nitride.