Using the VSEPR theory, predict the molecular structure of each of the following molecules.
(a)NI3
(b)AsH3
(c)OF2
What do you not understand about this? I think the structures can be found by googling for them.
a is a trigonal pyramid.
Why would b be different?
i cant seem to answers the first one. i keep getting the wrong answers. i put linear but its wrong. pls help
sorry i mean the last one. c. OF2. i put linear on this one but it was wrong
To predict the molecular structure of these molecules using the VSEPR (Valence Shell Electron Pair Repulsion) theory, you need to follow these steps:
Step 1: Determine the Lewis dot structure of the molecule.
Step 2: Count the total number of electron pairs (both bonding and nonbonding) around the central atom.
Step 3: Determine the electron pair geometry.
Step 4: Determine the molecular geometry.
Now let's apply these steps to each molecule:
(a) NI3:
Step 1: The Lewis dot structure of NI3 would look like this:
N
/
I - N - I
Step 2: Count the total number of electron pairs around the central nitrogen atom. In the Lewis dot structure, there are three bonding pairs (N-I) and one nonbonding pair (lone pair) on the central atom.
Step 3: Determine the electron pair geometry. With four electron pairs around the central atom, the electron pair geometry is tetrahedral.
Step 4: Determine the molecular geometry. Since all three bonds and the lone pair are in a tetrahedral arrangement, the lone pair of electrons will cause a distortional effect, resulting in a trigonal pyramidal molecular geometry. So, the molecular structure of NI3 is trigonal pyramidal.
(b) AsH3:
Step 1: The Lewis dot structure of AsH3 would look like this:
H H
\ /
As
|
H
Step 2: Count the total number of electron pairs around the central arsenic atom. In the Lewis dot structure, there are three bonding pairs (As-H) and zero nonbonding pairs.
Step 3: Determine the electron pair geometry. With three electron pairs around the central atom, the electron pair geometry is trigonal planar.
Step 4: Determine the molecular geometry. Since all three bonds are in a trigonal planar arrangement, there are no lone pairs causing distortions. Therefore, the molecular geometry of AsH3 is also trigonal planar.
(c) OF2:
Step 1: The Lewis dot structure of OF2 would look like this:
O
/
F - O
Step 2: Count the total number of electron pairs around the central oxygen atom. In the Lewis dot structure, there are two bonding pairs (O-F) and two nonbonding pairs.
Step 3: Determine the electron pair geometry. With four electron pairs around the central atom, the electron pair geometry is tetrahedral.
Step 4: Determine the molecular geometry. Since two bonds and two lone pairs are in a tetrahedral arrangement, the lone pairs will cause a distortional effect, resulting in a bent molecular geometry. So, the molecular structure of OF2 is bent.
By following the steps of the VSEPR theory, you can predict the molecular structures of these molecules.