consider the molecules PF3 and PF5.
b]is the PF3 molecule polar or is it nonpolar. explain
C] on the basis of bonding principles, predict whether each of the following compounds exists. In each case explain your prediction.
(i) NF5
(ii) AsF5
2. explain why the H-N-H bond angle is 107.5 degrees in NH3.
You need to tell me a little of what you think on these. The last question was a freebie but this one isn't.
hints:
for b, draw the Lewis electron dot structure for PF3 and that will tell you the shape. That will tell you if it is polar or non-polar.
For NF5 and AsF5, go through the Lewis dot structures.
i don't know
b] PF3 is polar because it contains polar bonds and is not symmetrical
2. H-N-H bond angle is 107.5 because in space everything is three dimensional. If you looked at a three dimensional molecule of H-N-H, you would see that the angle is greater than 90 degrees. When measured it turns out to be about 107.5 degrees.
PF3 Triangular pryramid shape thus is not symmetric yet PF5 is symmetric thus the molecule is not polar
what types of hybrid
orbitals are involved in the bonding of the silicon atoms in silicon tetrafluoride,SiF4?
Sure, let's go through each question step by step:
b) To determine if the PF3 molecule is polar or nonpolar, we can start by drawing the Lewis electron dot structure of PF3.
In the Lewis structure of PF3, phosphorus is the central atom with three fluorine atoms bonded to it. Phosphorus has five valence electrons, and each fluorine atom contributes one valence electron.
The Lewis structure of PF3 looks like this:
F
/
P
\
F
In PF3, phosphorus forms three single bonds with fluorine atoms. The shape of PF3 is trigonal pyramidal, with the phosphorus atom at the top and the three fluorine atoms forming a pyramid-like shape around it.
Since PF3 does not have a symmetrical arrangement of atoms, it is a polar molecule. The fluorine atoms exert a greater pull on the shared electrons, causing a partial negative charge to develop around the fluorine atoms and a partial positive charge around the phosphorus atom.
c) (i) NF5: To predict whether NF5 exists, we can examine the Lewis dot structure of NF5. Nitrogen has five valence electrons, and each fluorine atom contributes one valence electron.
The Lewis structure of NF5 would have nitrogen as the central atom with five fluorine atoms bonded to it. However, nitrogen is not capable of forming more than four covalent bonds. So, NF5 does not exist.
(ii) AsF5: Similarly, to predict whether AsF5 exists, we can examine the Lewis dot structure of AsF5. Arsenic has five valence electrons, and each fluorine atom contributes one valence electron.
The Lewis structure of AsF5 would have arsenic as the central atom with five fluorine atoms bonded to it. Arsenic can accommodate five fluorine atoms by using its d orbitals in addition to its valence orbitals. Therefore, AsF5 does exist.
2. The H-N-H bond angle in NH3 is approximately 107.5 degrees. This bond angle can be explained by the electron pair repulsion theory, specifically the VSEPR (Valence Shell Electron Pair Repulsion) theory.
In NH3, the central nitrogen atom is surrounded by three hydrogen atoms. Nitrogen has five valence electrons, and each hydrogen atom contributes one valence electron.
The electronic configuration of nitrogen in NH3 is as follows:
N: 1s2 2s2 2px1 2py1 2pz0
To minimize repulsion, the three hydrogen atoms arrange themselves in a trigonal pyramid around the nitrogen atom. The lone pair of electrons on nitrogen occupies one of the corners of the pyramid.
Since the lone pair of electrons repels more strongly than the bonding pairs, it pushes the bonding pairs closer together, reducing the bond angle. As a result, the H-N-H bond angle is less than the ideal tetrahedral angle of 109.5 degrees and measures around 107.5 degrees.
This bond angle is an observed consequence of the repulsion between electron pairs and can be explained by considering the arrangement of bonding and lone pairs around the central nitrogen atom in NH3.