Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms: atom Z* experienced by a valence electron.
An atom of sodium. (pick one)
An atom of chlorine. (pick one)
An atom of silicon. (pick one)
An atom of magnesium. (pick one)

Si > Al > Mg > Na

Explanation:

In an atom, there is the positively charged particle' the proton, the negatively charged particle; the electron and neutral charged particle; the neutron. The effect of the proton on an atom that is the ability of these positive particles to attract the negative[valence electrons] particles is known as Effective nuclear charge.

[1]. Electron configuration of Silicon, Si = (1s²2s²2p⁶) 3s²3p².

The configuration part of Si in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.

The total number of electrons = 14, the inner electrons= 10. Thus,  effective nuclear charge = 14 - 10 = 4.

[2]. Electron configuration of Aluminum, Al = (1s²2s²2p⁶) 3s²3p¹.

The configuration part of Al in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.

The total number of electrons = 13, the inner electrons= 10. Thus,  effective nuclear charge = 13 - 10 = 3.

[3]. Electron configuration of Magnesium, Mg = (1s²2s²2p⁶) 3s²

The configuration part of Mg in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.

The total number of electrons = 12, the inner electrons= 10. Thus,  effective nuclear charge = 12 - 10 = 2.

[4]. Electron configuration of sodium, Na = (1s²2s²2p⁶) 3s¹.

The configuration part of Na in bracket is known as the inner electrons while the ones without brackets are the outer/valence electrons.

The total number of electrons = 11, the inner electrons= 10. Thus,  effective nuclear charge = 11 - 10 = 1.