Question

Read the given expression.

X = atomic number − number of core electrons

Which of the following explains the identity of X and its trends down a group?

X is the effective nuclear charge, and it remains constant down a group.
X is the screening constant, and it remains constant down a group.
X is the effective nuclear charge, and it increases down a group.
X is the screening constant, and it increases down a group.

Answer 1

I think it is " X is the effective nuclear charge, and it increases down a group."