Between $2s$ and $2p$ electrons,which one experiences a greater shielding effect from inner shells?

The bromine atom possesses $35$ electrons. It contains $6$ electrons in $2p$ orbital,$6$ electrons in $3p$ orbital and $5$ electrons in $4p$ orbital. Which of these electrons experiences the lowest effective nuclear charge?

Which of the following statements is correct about the "shielding effect"?
$1$. It is effective when the orbitals in the inner shells are completely filled.
$2$. Inner shells do not show any effect.
$3$. With an increase of shielding down the group,ionization energy increases.
$4$. With increasing nuclear charge,the shielding effect increases.

Effective nuclear charge is maximum in case of

Explain the shielding effect with an example. Also,explain the $2s-2p$ approach in a group and a period.

The value of the screening constant for an electron in a $3s$ orbital is identical to that of an electron present in which of the following orbitals?