how do you draw the lewis structure for PBr3?
P has 5 valence electrons. Each Br has 7 valence electrons. This makes a total of 26 valence electrons. Put P in the middle. Attach the three bromines. You've used 6 of the 26 valence electrons in single bonds. You have 20 remaining. Each Br needs 6 while the P needs 2 more to become stable. This makes 20 which is how many you have remaining. Distribute the 20 as lone pairs and your structure is complete.
With difficulty on these boards. I will try.
Set up the molecule like this.
     Br
     |
Br-P-Br
then put two dots (like this :) for each - or | shown, add two more .. at the bottom of P, then add six .. or : areound each Br. I hope this helps.
To draw the Lewis structure for PBr3 (phosphorus tribromide), follow these steps:
Step 1: Count valence electrons
Determine the total number of valence electrons by adding the valence electrons of phosphorus (P) and bromine (Br). Phosphorus has 5 valence electrons, and each bromine atom contributes 7 valence electrons.
Total valence electrons = (5 valence electrons from P) + (3 bromine atoms x 7 valence electrons per bromine) = 5 + 21 = 26 valence electrons.
Step 2: Determine the central atom
In PBr3, phosphorus (P) is the central atom because it is least electronegative.
Step 3: Connect atoms with single bonds
Connect one bromine atom to phosphorus with a single bond.
P - Br
Step 4: Distribute remaining electrons
Place the remaining valence electrons around the outer atoms (bromine atoms) to complete their octets. In PBr3, there are 26 - 2 = 24 valence electrons remaining.
Place three lone pairs (three pairs of electrons) around each bromine atom:
P - Br
|
Br
|
Br
Step 5: Fill the central atom's octet
Place the remaining valence electrons as lone pairs around the central atom (phosphorus) to complete its octet. In this case, add one lone pair of electrons to the phosphorus atom.
P - Br
|
Br
|
Br
|
lone pair
Step 6: Check for octet completion
Count the total number of valence electrons. In the Lewis structure, we used 24 valence electrons. If the total number of valence electrons is equal to the initial count (26), then the structure is valid.
Thus, the Lewis structure for PBr3 is:
P - Br
|
Br
|
Br
|
lone pair
To draw the Lewis structure for PBr3 (phosphorous tribromide), you need to follow these steps:
1. Determine the total number of valence electrons:
- Phosphorous (P) is in Group 15, so it has 5 valence electrons.
- Bromine (Br) is in Group 17, so each bromine atom has 7 valence electrons.
Therefore, the total number of valence electrons for PBr3 is:
5 (P valence electrons) + 3 × 7 (3 Br valence electrons) = 26 valence electrons.
2. Start by placing the phosphorous atom in the center and surround it with the bromine atoms.
Br Br
| |
P --- Br
3. Place the remaining valence electrons around the atoms as lone pairs, so each atom has an octet, except phosphorous.
- Each bromine atom already has 7 valence electrons from step 1, so it needs 1 more electron to complete its octet. Place 1 lone pair (2 electrons) on each of the bromine atoms.
- Initially, all 26 valence electrons are used as lone pairs.
Br(•) Br(•)
| |
P --- Br
4. Check if the central atom (phosphorous) has an octet of electrons. It does not, as it only has 6 valence electrons.
5. To complete the octet for the central atom, convert one lone pair from a surrounding atom into a bonding pair by moving it to form a double bond with the central atom (phosphorous).
Br Br
| |
P = Br
6. After forming the double bond, check if each atom has an octet of electrons. Now, the central phosphorous atom has an octet, and each bromine atom also has an octet of electrons.
Therefore, the Lewis structure for PBr3 is:
Br Br
| |
P = Br
Note: In some cases, elements beyond the second period (like phosphorous in this case) can exceed the octet rule and have more than 8 electrons around them. However, in this particular molecule, phosphorous follows the octet rule.