## 2.93

Maria1E
Posts: 61
Joined: Sat Jul 22, 2017 3:01 am

### 2.93

I'm confused about the solution manual's assignment of the elements to the figures A,B,C, and D in the diagram. First of all, why would B be chlorine and A be sodium if chlorine is farther across the period than sodium is? I thought that atomic radii decrease across a period, so why would chlorine be assigned to B, the bigger circle?
Also, the solution manual says that the circle C is Na+, and circle D is Cl-. However, during lecture Dr. Lavelle said that cations are smaller than their parent ions and anions are larger than their parent ions. So why would Na+, a cation, be a bigger circle than Na while Cl-, an anion, is depicted smaller than Cl?

Thank you!

Ryan Sydney Beyer 2B
Posts: 82
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

### Re: 2.93

Solutions Manual Error! I copied this from the link on Dr. Lavelle's website titled Solution Manual Errors ::

In the picture, it shows A (smaller atom) + B (larger atom) --> C (larger ion) + D (smaller ion)

The solution manual says that A=Na and B=Cl, and it references Figure 2.20 which explicitly lists the atomic radius of Na to be 154 pm and the atomic radius of Cl to be 99 pm.

It also says that C=Na+ and D=Cl-, referencing Figure 2.22 which shows that the ionic radius of Na+ to be 102 pm and the ionic radius of Cl- to be 181 pm.

Error: A=Na; B=Cl; C=Na+; D=Cl Correction:A=Cl ; B=Na; C=Cl-; D=Na+

Return to “Trends in The Periodic Table”

### Who is online

Users browsing this forum: No registered users and 0 guests