For which of the following is $Z_{eff}$ equal to $Z$?

In a given shell,the order of screening effect is

How does the orbital energy change as the nuclear charge increases from $Ne$ to $Ca$?

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.

In $Lithium$,the $2s$ electron experiences a force of attraction exerted by the nucleus that is:

The screening effect of inner electrons of the nucleus causes