AAMC SEction Bank Discrete Question 25 C/P

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lotus0618
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AAMC SEction Bank Discrete Question 25 C/P

Post by lotus0618 » Thu Jul 16, 2020 11:22 am

Discrete qeustion after passage 3

I thought we always remove electrons from the highest energy level, and 3d is higher energy than 4s (if you look at the attached picture I found on google, 3d is higher energy than 4s).

thanks
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NS_Tutor_Yuqi
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Re: AAMC SEction Bank Discrete Question 25 C/P

Post by NS_Tutor_Yuqi » Sun Jul 19, 2020 12:37 pm

Hey! This is not an intuitive topic at all, but what you said is right only when we're building orbitals. When we're taking electrons away, then we take from the s orbital first. Here is a website that explains this in greater detail.
https://chem.libretexts.org/Bookshelves ... s_Orbitals
lotus0618
Posts: 182
Joined: Sun Dec 29, 2019 5:47 pm

Re: AAMC SEction Bank Discrete Question 25 C/P

Post by lotus0618 » Sun Jul 19, 2020 2:12 pm

Hi! I don't have much time left till my exam, but I did skim over the article you showed it to me. Here are the rules I need to know in regards to the transitional metals. Can you please check them to make sure I have everything down?
a. when the transitional metals donate electrons, I remove electrons from their 4s orbitals first INSTEAD OF their 3 d orbitals
b. Only Cr and Cu are when I need to move one electron from their 4s orbital to 3d orbital to make it a 3d10.

Are there any 'weird' things that I need to know about the transitional metals? thanks
NS_Tutor_Nancy
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Re: AAMC SEction Bank Discrete Question 25 C/P

Post by NS_Tutor_Nancy » Thu Jul 23, 2020 9:37 pm

Hey!

I don't know if this qualifies as "weird" exactly, but electron configurations can be a little bit different in the transition metals. The key is that elements want a full orbital, or a half-filled orbital, these are more stable configurations. So for Cr, the electron configuration is [Ar] 3d5 4s1 (instead of [Ar] 3d4 4s2). The entire group follows this rule. Similarly, for Cu, the electron configuration is [Ar] 3d10 4s1 (instead of [Ar] 3d9 4s2) and the entire group follows this rule.

I hope this helps!
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