Home work question 3.39

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Delilah Naranjo dis 3j
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Joined: Wed Sep 21, 2016 3:00 pm

Home work question 3.39

Postby Delilah Naranjo dis 3j » Wed Oct 19, 2016 9:23 pm

Write the complete Lewis structure for each of the following compounds: ammonium chloride; potassium phosphide; sodium hypochlorite.

Someone please help me and if you can explain step by step that would be great thanks.

Lexi Nadler 1H
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Joined: Fri Jul 22, 2016 3:00 am
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Re: Home work question 3.39

Postby Lexi Nadler 1H » Thu Oct 20, 2016 10:32 am

Ammonium Chloride is written as NH4Cl.
1. Count the number of valence electrons
(N=5) + (H=1x4) + (Cl=7) = 16 electrons
2. Take each chunk at a time. NH4 has 9 electrons, 1 too many, so it can donate one to Cl to complete its octet.
3. Now NH4 has 8 electrons and a positive charge because it lost an electron.
4. You make N the central atom and connect each Hydrogen atom with a single bond. Write the positive charge.
5. Write out the Cl^- ion as the Cl atom with 8 valence electrons. Write the negative charge.
6. Now count all the electrons to make sure we did it write. By counting the double bonds and the lone pairs, it adds up to 16.

Sangita_Sub_3H
Posts: 23
Joined: Sat Jul 09, 2016 3:00 am

Re: Home work question 3.39

Postby Sangita_Sub_3H » Thu Oct 20, 2016 11:59 am

Potassium Phosphide is written as K3P.

1. First, you see that there are 3 K atoms and I P atom.
2. For K, there is only 1 valence electron, so multiplying one by three, you get 3 valence electrons for K.
3. For P, there are 5 valence electrons. Adding the P valence electrons to the K, you get 8 valence electrons.
4. Keeping P as the central atom (since it has the lowest ionization energy), you place all of the K atoms around it.
5. After drawing the lines connecting the K atoms to the P (which uses up 6 electrons), you should be left with 2 valence electrons to place. However, in order to know where to place them, you need to calculate the formal charges of each element with the equation FC = V - (L+S/2), which represents Formal Charge = Valence electrons - (lone pair + shared electrons/2). The goal is to obtain a formal charge of zero for all of the atoms since that is the most stable state.
6. Using that equation for K including the line, you get FC = 1 - (0+2/2) =0. For P, you get FC = 5 - (0+6/2) = 2. However, by adding the 2 valence electrons to P, you would end up with a formal charge of FC = 5 - (3+6/2) = 0.
7. So, in the end, the structure would have the P in the middle with two dots representing the two valence electrons surrounded by three Ks by way of shared electrons(lines).

Hope this helps!

Camille 4I
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Joined: Sat Aug 24, 2019 12:18 am

Re: Home work question 3.39

Postby Camille 4I » Fri Nov 01, 2019 9:48 am

How can you determine that the formula for ammonium chloride is NH4Cl?


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