## Finding the Length of the Bond/Is this on the midterm? [ENDORSED]

Ananta3G
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### Finding the Length of the Bond/Is this on the midterm?

How do you do this: Use the covalent radii in Fig. 2D.11 to calculate the bond lengths in the following molecules. Account for the trends in your calculated values: (a) CF4 (b) SiF4 (c) SnF4. Thank you!

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### Re: Finding the Length of the Bond/Is this on the midterm?  [ENDORSED]

The figure shows a periodic table with the common bond lengths of some elements. So for CF4, each bond is a single bond between C and F (draw the lewis structure to know that). You just go to the table, find the values for a single bond C and for F, and add the numbers together. The length of a single bonded C is 77 while the length for F is 58. 77+58=135 so the length is 135 pm.

SiF4 has Si in the middle, singly bonded to 4 F. The length of Si is 111 and F is 58 so the bond length is 169 pm.

SnF4 has Sn in the middle, singly bonded to 4 F. The length of Sn is 141 and F is 58 so the bond length is 199 pm.

The trend this illustrates is that atomic radius increases down a group (because there are more atomic shells). If atomic radius increases, bond length also increases.