!!! which element has three occupied quantum shells with 4 electrons in the outermost

Argon. If you look at the periodic table, the noble gases (column on the furthest right of the table - labeled column 18) have fully filled electron shells. This is why noble gases (helium, neon, argon, krypton, xenon, and radon) are not very reactive with other elements - they are happy with their fully filled electron shells. So, the third element down on the noble gas column (Argon) has 3 fully filled electron shells. Periodic table courtesy of Wikipedia

(taken from Quora)

Answer : The volume of the balloon at STP is, 2.04 L

Explanation :

First we have to calculate the moles of dry ice.

Molar mass of dry ice = 44 g/mol

Now we have to calculate the volume of dry ice.

As we know that 1 mole of substance contains 22.4 L volume of gas.

As, 1 mole of dry ice contains 22.4 L volume of gas.

So, 0.0909 mole of dry ice contains 0.0909 × 22.4 L = 2.04 L volume of gas.

Thus, the volume of the balloon at STP is, 2.04 L