VSEPR theory predicts that the geometry of AsH3 molecule is which of the following.
linear
trigonal planar
trigonal pyramidal
tetrahedral
please explain the correct answer
trigonal pyramidal
Can you draw the structure? I can't on this forum.
https://www.google.com/search?q=structure+AsH3&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb
Looks trigonal pyramidal to me.
The VSEPR (Valence Shell Electron Pair Repulsion) theory predicts the molecular geometry by considering the repulsion between electron pairs around the central atom.
To determine the geometry of the AsH3 (arsine) molecule, we first need to identify the Lewis structure. Arsenic (As) is the central atom, and it has three hydrogen atoms (H) attached to it.
The Lewis structure of AsH3 would look like this:
H H
\ /
As
|
H
In the Lewis structure, we can see that there are three bonding pairs (between As and H) and one lone pair of electrons on the central atom, As.
According to VSEPR theory, the presence of three bonding pairs and one lone pair around the central atom leads to a trigonal pyramidal molecular geometry.
Therefore, the correct answer is "trigonal pyramidal."
To determine the geometry of the AsH3 molecule using the VSEPR (Valence Shell Electron Pair Repulsion) theory, we need to follow a few steps:
1. Identify the central atom: In this case, the central atom is As (arsenic).
2. Determine the total number of valence electrons: Arsenic belongs to Group 15 (Group VA) in the periodic table, so it has 5 valence electrons. Hydrogen, on the other hand, belongs to Group 1 (Group IA) and has 1 valence electron each. Since there are 3 hydrogen atoms, the total valence electron count becomes 5 + (1 × 3) = 8.
3. Find the electron geometry: To do this, we need to consider both the bonding and non-bonding pairs of electrons around the central atom. In AsH3, there are 3 hydrogen atoms bonded to arsenic, meaning we have 3 bonding pairs. Since there are no lone pairs on arsenic, the total electron pairs are 3.
4. Determine the molecular geometry: Now we consider only the bonding pairs. With 3 bonding pairs, we use the VSEPR theory to find the arrangement of these electron pairs. In this case, with 3 bonding pairs, the molecular geometry is trigonal pyramidal.
So, the correct answer is "trigonal pyramidal."