## Chapter 7 – Periodic Properties of the Elements: Part 1 of 11

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In this video I’ll teach you about “effective nuclear charge,” also called “Z-effective” or “Zeff”. I’ll also show you how to calculate “effective nuclear charge” by introducing you to a few Zeff problems.

nana dauod says:

Can I just say thank you for your videos…
You really helped me ALOT

mo1 says:

Your a good teacher, Thank you for sharing your lectures on here.

Destiny Iwuajoku says:

Where is the link to the problem set questions?

tamara charles says:

I'm from the caribbean. Your videos the reason i have an A thus far. Thank you !! your videos are awesome!!

A.srihari A.Srihari says:

☺👌very important for all students this chapters

A.srihari A.Srihari says:

very interesting topic s

Tevfik Sevgin says:

What about 0.35,0.85 stuff with Zeff ?

Veronica Scott says:

Hi, I was wondering about trends in Zeff among the periodic table.

It makes sense that moving across a period from left to right would result in greater Zeff because the number of electrons in lower energy orbitals remains the same (s), while nuclear charge (Z) increases by +1 for each successive element. If this reasoning is wrong, please correct me!

Mathematically, I want to say Zeff (=Z-s) essentially remains the same, moving down a group in the periodic table. Intuitively, I was to say Zeff (being the measure of strength of attraction between an electron and the protons in the atom's nucleus) decreases because the valence electrons are in larger orbitals at increasing distances from the nucleus. However, my text (and other online resources I found hastily) state that Zeff actually increases down a group, while the electrostatic attraction between the nucleus and valence electrons decreases. What is your take on trends in Zeff down a group in the periodic table? I'm not sure what to think given all the discrepant information.

Finally, what is the difference between electrostatic force and Zeff? Am I mistaking them for the same thing by assuming Zeff is virtually a measure of electrostatic attraction? It seems that way, given what my text asserts.

Thanks for the videos and extra help!! You're great at what you do.

cando high says:

there is no visual effects. this is a poor video.

Omg Thank you so much for these videos. These are the only reasons why I pass chem. Thank you so so much!

Jenniffer Avila-Bravo says:

very helpful video for my AP Chem class thank you

hussein335 says:

Is this general chemistry for college?

Halil BALIM says:

I don't understand the sentence that is at the 6:26 : "When calculating S, electrons in the same orbital as the electron in question don't count. They're given a value of zero.

Meher Khan says:

Oh my God these videos are the only reason why I haven't lost my mind in Chem class yet…Forever Grateful for these 🙂

Mohammed Talha says:

0 dislikes in your video sir AWESOME

Anderson Souza says:

No student, you understood everything i taught you perfectly!

Antoine Rayer says:

sir
can you explain ionization enthalpy and screening effect.

where is D second part of dis video sir

majd firas says:

Dude I used to hate nothing more than chemistry!!! After watching your videos i swear to god i feel like chemistry is a game to me

Can never thank you enough Mike!

Science Tutor says:

Well you can watch this video to clearly understand the concept with a simple demonstration. I really find it very helpful. Plus you dont have to read long answer. Just watch this interactive video… http://bit.ly/1vS6ORx