Effective Nuclear Charge, Shielding effect, & Periodic Properties Tutorial; Crash Chemistry Academy

[@Emoney131]

wow, I hope you still can see this comment. this was a perfect explanation of the subject. thank you for posting this!

[@pantoastado1264]

Sir, I came into this thinking there was no way I would ever understand this, and left with confidence. Truly, this is the best video on the internet on this topic, and I wish I could shake your hand, lol!

[@CrashChemistryAcademy]

Thanks so much, I appreciate the comment!

[@norfro]

This video deserves a KZbin Oscar! I finally understand this subject. Thank you!!

[@UserName-pi9no]

I like your pacing on this video, It really makes sure you understand without repeating itself too much.

[@dylanhicks3212]

Incredible video! Best I have seen on the subject.

[@thlamuanpuiarenthlei2436]

THIS IS ONE OF THE MOST HELPFUL VIDEOS EVER KZbin teachers are the best

[@CrashChemistryAcademy]

🙂

[@keniagiselle]

Incredibly helpful!! Had to leave a comment because I have been looking for videos to explain Zeff and this is the only on I came across that explained it not only in detail but in a way I completely understand it now. Thank you so much!!

[@zenakishawi9137]

Thank you so much for this video!! My exam is in 2 days and no matter how many times I read the textbook, notes and slides for the course, I couldn't grasp my head around this concept. I'm very grateful to find you're videos

[@CrashChemistryAcademy]

You're welcome and thank you! Glad it was helpful!

[@iambicgatchster1852]

Thank you so much for making this! It has been a difficult concept for me, and my textbook has not been helpful. This video is extremely helpful in understanding the concept. PS... I love your other videos!

[@mmmmmmmm4360]

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[@thendralprabu2172]

Thank you so much for your help! I had a lot of trouble grasping the concept until I came across your video. I'm using your video to help me before my test, so I really appreciate the simple way you explained the concept.

[@DAFGALD96]

Amazing video, super detailed. It helped me so much in studying for my chemistry test, thank you!

[@chainzss]

thanks to this video, i finally understand this concept. have been staring at my notes for hours...

[@agustinjaysoncadag]

The two are very important concepts to understand periodicity. I struggled understanding shielding and Zeff but you made it easier.

[@sheldoncooper4204]

Oh my god! Thank you so much!!! You have no idea how much you’ve helped me.

[@tahsinintisardhrubo9606]

Sir, I must thank you for this amazing video! But I had one more thing to say. It would have been a great pleasure if explain the concepts of orbits in detail with visualizations.

[@CrashChemistryAcademy]

The video necessarily uses the “shell model” of electrons to get the point across, which unfortunately implies that electrons have orbits, which they do not. Electrons exist in proscribed 3-dimensional spaces called (unfortunately!) “orbitals”. Please see my video on orbitals for a discussion of how electrons exist within the atom- Orbitals, the Basics: kzbin.info/www/bejne/e6jJaIWii7N1iaM

[@tahsinintisardhrubo9606]

@@CrashChemistryAcademy Thank you very much Sir! I really appreciate your kind cooperation.

[@CrashChemistryAcademy]

Hope it helps!

[@kiptoocollins8430]

Thanks so much I have improved more in understanding Chemistry with KZbin

[@the81kid]

This really is very informative and well explained. This seems to be one of the best learning youtube channels. Many thanks!

[@CrashChemistryAcademy]

Thanks for your very nice comment!

[@phuongphan794]

I can tear this part off my text and skip class for another day. Millions thanks.

[@viively7]

FINALLY! a video that explains all the essentials of Zeff without complicating it

[@Andrew-gx6pw]

These videos really provide clarification.

[@tana4043]

Well explained. I finally understand this concept!! Huge thanks.

[@sandom.__.2]

I CAN'T CONVEY TO YOU HOW MUCH THIS VIDEO HAS HELPED ME!! THANKS A LOT :D

[@CrashChemistryAcademy]

I'm very glad it helped!

[@khamtruong2086]

Best video i have found yet. Thanks so much

[@KKone72]

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[@RaggedyRosemary]

This vid really helped, your explanation is very detailed and easy to follow im gonna refer to ur channel for my chem problems now :)

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I am extremely grateful for videos like yours, you are truly an MVP! greetings from So Cal

[@CrashChemistryAcademy]

Thanks! From NE Illinois

[@Zeuts85]

This is fantastic! What a wonderful explanation.

[@MahmoodSaeedB]

Thanks very much for great explanation but I still have some some questions: 1) You said that "Zeff is approximately curtain going down the alkali metals". What is the most accurate way to calculate it if the formula of (zeff = z - s) (where s is the inner electrons) is not very accurate because valence electrons feel greater repulsions due to greater shielding then the nuclear hold on valence electrons decreases going down a group? 2) I still have issues regarding the periodic trends in the transition elements because the size is not completely curtain going left to right? Looking at the sizes of the first transition series goes me crazy (especially when they elements after Chromium started to be quite steady in size and then increase with Copper and Zinc)! In summary, What I seek for is a formula that takes all the factors, number of protons, number of electrons, number of shielding electrons, repulsion, and any other factors that I don't know about and put them together and calculates precisely the radius of the atom. Is that possible?? If you don't have a problem, I would like to know your opinion about this question that really perplexed me: Scandium is distinguished from the element that follows it in the series by the following: a) The repulsive forces between electrons have a greater effect than the effective nuclear charge. b) The effect of the effective nuclear charge is greater than the effect of the repulsive forces between electrons. c) The effect of the effective nuclear charge is at its maximum. d) The repulsive forces between the 3d electrons are at their minimum.

[@CrashChemistryAcademy]

1) you would have to look up how to calculate s, which should be in any university-level introductory text. Then you could get a more accurate trend in Zeff. 2) The lack of concrete trends in the transition metals has to do with the fact that electrons are not being added to the valence shell, they are added to the core. As electrons are added to the core (along with added protons), the stability of the atom changes with regard to the amount of unfilled/half-filled/filled core orbitals, and that variation in stability is manifested in atomic radius which in turn affects other properties such as reactivity and electronegativity. I do not know of any formula to that would generate property values close to measured values, but that does not mean there isn't one. Find the radius of scandium and the element that follows it. The difference will give you the answer to your multiple choice.

[@MahmoodSaeedB]

@@CrashChemistryAcademy I truly appreciate your time and assistance. ❤❤❤❤ Scandium has a larger atomic radius than Titanium, meaning that the increase in electron repulsion in Titanium is smaller compared to the rise in positive charge. However, I can't find a choice that expresses this idea accurately.

[@pranhav]

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[@CrashChemistryAcademy]

Thanks! I will look into it.

[@pravinmahajan5834]

The Best way to calculate Zeff. You are really Great SIr. Thank you soooooo much

[@naomio01]

Thank you for giving us visuals, something was off and this took me all week to understand.

[@srushtighadge3105]

thank u so much!!! this is really helpful😊😊

[@unknownhuman2073]

Best explanation got everything in just first watch

[@michaelayeni177]

Thank you for not using separate videos to show the content. The lead up to ionization energy was fabulous!!!!!!!!

[@CrashChemistryAcademy]

Thanks!

[@sea5205]

This is a really well explained video, thanks!

[@tamarao.7197]

That is what I've been looking for. Thank you so much for making it this clear.

[@CrashChemistryAcademy]

You're welcome! Thanks for your comment.

[@pkre707]

This video is so much better than my lecture on this.

[@jaquelynborcea3630]

Amazing explanation for such a complicated chem topic. This helped me soooo much. THANK YOU!!

[@CrashChemistryAcademy]

You're welcome!

[@Lachantefleuriee]

Up to the point & concise. Thanks for uploading this. Helped me alot

[@CrashChemistryAcademy]

Thanks!

[@aboundlessworker.mazhar]

U really have a great sense of teaching❤of how even less than average high school students including me could 60 to 70% understand this concept😅

[@diggercoolbuddy6013]

most understanding. clear and neat video .thank you so much to making this video hope that you other videos are also better like this

[@gracenzaloudek2550]

I am so grateful for this video. It helped me so much! Thank you

[@CrashChemistryAcademy]

You're welcome, I'm glad it helped!

[@thetruedjlivewire]

so the loose valence electrons act like iron surrounding a magnet or otherwise core structure valence electrons. that being said, aside from shielding specifically, the domain of said electrons would abide by formations of macro motive force.

[@shivamshrivastav685]

incredible video bravo

[@SeanGhaeli]

Great video. Prof really bombed the lecture.

[@bharatverma3267]

Thankyou sir to make us understand about the concept

[@alexrosellverges8345]

Absolutely awesome video, thank you very much sir!

[@cephas3408]

In fact, sir you are the best!

[@cocogoatmilk1514]

This video is fantastic. Thank you so much.

[@df4250]

Again. Where were you when I needed you? :) Beautiful explanations. The content of this video is related to a question I asked about your video on metallic element electron behaviour. Asked in terms of ionisation energy, is it this energy that determines whether the valence electrons of an element behave by forming covalent bonds as against the less defined wanderings of electrons in metals?

[@CrashChemistryAcademy]

Not exactly. That is more in the realm of electronegativity, although the two are related. See my reply to your comment in the metallic bonding video.

[@bobbleheadgary]

You are the In"chemical" Hulk. thank you doc.

[@haajermonir3936]

i have never understood this topic as well as i do now thanks a lot

[@aniruddhamandal6971]

Thank you very much for this video .(I am from India)

[@piyushsrivastava2688]

I was too confused on this topic but after watiching your video my confusion got vanished

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Woahhh!!! You nailed thiss dudee!! 💯💯💯💯💯

[@CrashChemistryAcademy]

😊

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perfect explaining.i appreciate your efforts

[@ripan110]

very well explained!! thank you so much

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A great thumb up to the publisher!!

[@thechosen123isme]

Very clear explanation! Thanks.

[@anaconda470]

I started to refresh all the chemistry knowledge and your video is so helpful.

[@ganesh9714]

Tq sir it was very interesting topic

[@dewiih6663]

this video is the best on this subject, thank u

[@user-pv3cn7xo1i]

core electrons are electrons that are not in outermost shell?

[@jessz-4453]

pictures just hit different thanks!

[@naser_hashim]

You have just saved my life

[@fatimalearns9618]

How equal amount of electrons and protons are added as we move across a period and down the group? 13:00

[@CrashChemistryAcademy]

The atomic number represents the amount of protons, and in a neutral atoms that is also the amount of electrons. As you move across a period, the atomic number increases by 1 for each element, and so another proton and another electron has been added for a neutral atom. Going down a group, for example from fluorine (#9) to chlorine (#17), the increase in protons is 8 (=17 - 9) and so that is also the increase in electrons as well.

[@kaansametguler6258]

good video. nicely explained and connected.

[@DrHumzaAIIMS]

Great video sir

[@tb2748]

Could you explain the lanthanide contraction? I don't get why Au has a smaller bonding atomic radius than Sc. My textbook says it has to do with shielding and that 4f orbitals are being filled, which causes an increase in Zeff. But I thought that the increase in core electrons, 4f electrons, would cause more repulsion, making Au have a bigger radius.

[@mursyidahxa]

Thank you for the explanation!!!

[@ankurgandhi6456]

simply top level!

[@cinderellab4410]

What about the "decreased attractive force as distance increases with energy level" aka "inverse square law" argument used to explain trends down a group?

[@CrashChemistryAcademy]

I specifically state that among the factors in the trends discussed are distance from the nucleus and the resulting change in attractive force. This is Coulomb's Law, although I did not specifically state the law, but things were getting a bit complicated.

[@johanneskoevoet3504]

Thank you for making and sharing this!

[@CrashChemistryAcademy]

You are welcome!

[@maaheshparmar9928]

It was really helpful thankyou so much sir

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Thank you very much. Nice modeling.

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Really helpful, God bless you!

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[@CrashChemistryAcademy]

Thanks for your comment!

[@collinpereira2546]

Thanks this was very helpful!

[@Cloud-ow4jr]

Thank u so much sir.. this helped me a lott

[@CrashChemistryAcademy]

Thanks! You're very welcome.

[@NehPandya]

According to our theory atomic size should increase in groups from top to bottom but in group 13 Aluminium has atomic radius 143 pm and Gallium has atomic radius 135 pm which is less WHY??????

[@CrashChemistryAcademy]

Since size is intimately related to shielding and the number of protons, lets look there. Aluminum has no d electrons, and so the shielding of its three valence electrons comes only from the core ten electrons of the neon configuration. With gallium you have suddenly added another 18 electrons and protons. Ten of those are d electrons (three are valence--s2p1), but the d orbital energy is quite close to that of s, and the d electron positions are also, on average, close to the s electrons, which reduce the effect of their shielding. The result is those added 18 protons have a larger attractive affect (greater Zeff), bringing the electrons closer to the nucleus and reducing the radius. So to sum it up, the difference is the presence of d electrons.

[@CrashChemistryAcademy]

Because there is such a wide variety of ways to measure/calculate radii, you may be comparing two different methods. Almost all methods have Ga larger than Al. Look at webelements.com for a comprehensive list.

[@hunterthorne4671]

Why don't we always say zeff is the number of Valence electrons instead of calculating it all the time...?

[@jennabui2233]

well done, thank you very much for your help

[@sulezakaria7312]

Excellent work

[@Patrick-pt2vq]

I applaud this one

[@dumplingsoup4914]

amazing explanation!

[@damonrothschild5270]

16:34 electrons are NOT added to the nucleus. I think you meant to say when protons are added to the nucleus not electrons.

[@CrashChemistryAcademy]

Thanks, will have to add a correction!

[@havishisukapalli6411]

very nice explanation.

[@fajarreema4815]

كثر الله خيرك على شغلك ذا

[@CrashChemistryAcademy]

شكرا على تعليقك، شكرا على المشاهدة.

[@mahinshahrier7022]

very well done! thank you

[@piyushaspiretoachieve3179]

I would like to interrupt you that you have not mentioned the exception of noble gases and trend of noble gases shown in your video. Is wrong.I came here to know the exception of 3de- … if you have made video on this how these electron change the trend then please share thank you!!

[@CrashChemistryAcademy]

You may be thinking of covalent radius. I have presented the trend in atomic radius which is slightly different. The covalent radius has noble gases larger than their halogen neighbors, which disrupts the trend. However I have used atomic radius, not covalent radius, which keeps the period trend in size all the way to noble gases.

[@piyushaspiretoachieve3179]

@@CrashChemistryAcademy but bro atomic radius types are only covalent , metallic , ionic radius… etc then I didn’t understand how you depicted the atomic radius and for noble gases at its basic level only it’s van der wal radius can be measured ….. if am I not right at any point you can point out me

[@CrashChemistryAcademy]

@@piyushaspiretoachieve3179 Van der Waals is what I used (sorry I was not more specific) and while more accurate for noble gases, the Van der Waals radius for other atoms can be reliably reported via theoretical calculations.

[@piyushaspiretoachieve3179]

@@CrashChemistryAcademy yes thanks 👍

[@MelissaMaiga]

GREAT VIDEO!

[@houriak848]

Sir really i can't understand within a period we say that the radius gets a smaller but if we apply this rule on the period four for example SC and ti in this two elements there's 4s2 SC with 3d1 and ti with 3d 2 so the external electrons of sc of 4s there's a force of repulsion by 19 electrons and ti repulsion by 20 so the radius of ti is bigger than SC ??

[@CrashChemistryAcademy]

without looking up the two radii, I can at least tell you they are extremely similar, but likely Ti is SMALLER than Sc. While Ti adds an electron to 3d, it also adds another proton to counteract that added repulsion of the 20th electron. Across the d elements the size generally decreases, but not by much. d elements add both repulsion (added inner electrons) and attraction (added protons), and the quantum mechanics tells us the added attractive force slightly overcomes the repulsion of the added inner electron.

[@maaheshparmar9928]

plz upload a video for ionization enthalpy

[@MrMikael1337]

when you talk about Z_eff, you take into account both the shielding and the attractive force from the nucleus, but when you talk about IE you only take into account the shielding and NOT the attractive force. how come?

[@akshaygm841]

very good explanation

[@pastalavista5628]

THANK YOU SO MUCH YOU SAVED ME

[@soumyamishraroll9678]

Thank you sir.this video appeased my queries undoubtedly.

[@zainabmehdi6380]

I wanted to ask what is the exact trend if shielding effect across the period ( lithium to neon or sodium to argon)?? does it remain same or it decreases?? cz in some sources like internet n books they say it remains same across period... n some state it decreases cz effective nuclear charge increases. so it wud be nice if give a clear cut answer. cz it always confuses me ...thanks

[@CrashChemistryAcademy]

Defining shielding as the number of core electrons means that across periods 2 and 3 shielding is constant since the number of core electrons remains constant (2 core e- for period 2 and 10 core e- for period 3). Calculating Zeff as protons-core electrons, then Zeff increases across periods 2 and 3 since the number of core electrons remains constant but protons increases. Using S you would find the same, an increase, but the amount of increase depends on how you calculate S.

[@mohammedali]

Thanks!!! Great detailed explanation!! My chemistry teacher explained something with 0.35 x the electrons?? I didn't understand that. If you would explain that would be great.