Which group elements have the smallest atomic radii in their respective periods?

What happens to the size of atoms in p-block elements when we move from left to right in the same period?

Which of the following order of dipole moment for stated molecules is correct?

Calculate the compressibility factor of $1$ mole of a certain real gas if it occupies $0.4 \text{ dm}^3$ at $300$ K and $40$ atm. [R $= 0.082$ atm $\text{dm}^3 \text{K}^{-1}\text{mol}^{-1}$]