Ch. 2 Textbook Question 45d.  [ENDORSED]

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Ch. 2 Textbook Question 45d.

Postby Courtney_Koenig_3K » Tue Oct 18, 2016 5:00 pm

Which elements are predicted to have the following ground-state electron configurations.

d) [Rn]7s^2 6d^2

In the periodic table in the textbook both thorium and rutherfordium have this configuration, but the solutions manual says that the answer is thorium. How do I know which one it is if they have the same configuration.

And how do they have the same configuration if they have different numbers of electrons(Th=90, Rf=104)?

Pauline Tze 3B
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Re: Ch. 2 Textbook Question 45d.  [ENDORSED]

Postby Pauline Tze 3B » Tue Oct 18, 2016 6:04 pm

I think your error stems from reading the periodic table incorrectly. Rf and Th do have different electron configurations, which are Rf: [Rn] 5f^14 6d^2 7s^2 and Th: [Rn]7s^2 6d^2.

The periodic table's trends follow increasing atomic number. You need to read the f-block before the rest of the d-block when you get to Periods 6 and 7 (thus each of those periods has 32 elements) This visual should help:

Hope that clears things up.
Screen Shot 2016-10-18 at 5.59.05 PM.png

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