(a) If the core electrons were totally effective at...

(a) If the core electrons were totally effective at shielding the valence electrons and the valence electrons provided no shielding for each other, what would be the effective nuclear charge acting on the $3 s$ and $3 p$ valence electrons in $\mathrm{P}$ ? (b) Repeat these calculations using Slater's rules. (c) Detailed calculations indicate that the effective nuclear charge is $5.6+$ for the 3 s electrons and $4.9+$ for the $3 p$ electrons. Why are the values for the $3 s$ and $3 p$ electrons different? (d) If you remove a single electron from a $\mathrm{P}$ atom, which orbital will it come from? Explain.

(a) If the core electrons were totally effective at shielding the valence electrons and the valence electrons provided no shielding for each other, what would be the effective nuclear charge acting on the $3 s$ and $3 p$ valence electrons in $\mathrm{P}$ ? (b) Repeat these calculations using Slater's rules.
(c) Detailed calculations indicate that the effective nuclear charge is $5.6+$ for the 3 s electrons and $4.9+$ for the $3 p$ electrons. Why are the values for the $3 s$ and $3 p$ electrons different? (d) If you remove a single electron from a $\mathrm{P}$ atom, which orbital will it come from? Explain.

Key Concepts

Effective Nuclear Charge

Effective nuclear charge is the net positive charge experienced by an electron in an atom. It takes into account both the total number of protons in the nucleus and the shielding effects of other electrons, leading to a reduced effective attraction felt by the electron compared to the full nuclear charge.

Electron Shielding

Electron shielding refers to the phenomenon where electrons in inner shells or other orbitals repel electrons in outer shells, reducing the net attractive force exerted by the nucleus. This reduction in attractive force leads to differences in the effective nuclear charge felt by different electrons in the atom.

Slater's Rules

Slater's rules are guidelines used to estimate the effective nuclear charge acting on an electron in a multi-electron atom. These rules provide a systematic way to calculate the amount of shielding contributed by other electrons, taking into account their positions and distributions in various orbitals.

Orbital Penetration

Orbital penetration is the concept that electrons in orbitals with greater penetration into the region close to the nucleus experience a higher effective nuclear charge because they are less shielded by other electrons. Different types of orbitals (for example, s versus p orbitals) can therefore experience different effective nuclear charges even within the same energy level.

Ionization and Electron Removal

Ionization involves removing an electron from an atom, and the choice of which electron is removed depends on its energy and relative shielding. Electrons in orbitals with higher energies and lower effective nuclear charges are generally less tightly bound, making them the most likely candidates for removal during ionization.

Transcript

00:01 In this question, we are asked to do some work with effective nuclear charge.

00:05 In part a, we're given the following information.

00:11 If the core electrons were totally effective at shielding, the valence electrons, and the valence electrons provided no shielding for each other, what would be the effective nuclear charge acting on the 3s and the 3p valance electrons in p? okay, so element p is 15.

01:28 So in element p, the first thing i'm going to do is write the electron configuration.

01:36 When i'm working with the effective nuclear charge, i like to write the whole thing out unless it's too long.

01:48 So 15, well, i better do this first.

01:55 Okay.

01:58 So if we take a look at these electrons, these are my valence electrons, and they contribute zero to the shielding.

02:03 These are my core electrons and they're 10 times 1.

02:08 So i'm going to change colors and i will do my calculations right here.

02:15 15 minus 10 equals 5.

02:19 My effective nuclear charge will be positive plus 5.

02:23 It's always positive.

02:26 Okay.

02:27 For b, let's go with a blue.