NF2- has (2, 3, 4) regions of high electron density and (2, 4, 6) bonded electrons.
4 regions of high electron density because of the 2 bonds (each connecting a fluorine to the central atom of nitrogen) and the 2 unshared pairs of electrons on nitrogen
4 bonded electrons
right
To determine the regions of high electron density and bonded electrons for NF2-, let's first understand the Lewis structure of NF2-:
1. Nitrogen (N) is the central atom since it is less electronegative than fluorine (F).
2. Nitrogen has five valence electrons, and each fluorine atom brings seven valence electrons.
3. The charge of the molecule is -1, indicating an extra electron.
Now, let's proceed with the Lewis structure:
1. Start by placing the electrons around the atoms in pairs (one from N and one from F).
- N: ●
- F: ● ●
- F: ● ●
2. Next, distribute the remaining electrons to fulfill the octet rule.
- N: ● ● ●
- F: ● ●
- F: ● ●
3. Since there is an extra electron (negative charge), add it to the central atom (N).
- N: ● ● ● ●
- F: ● ●
- F: ● ●
Now, we have the Lewis structure for NF2- with one lone pair on the central nitrogen atom.
To identify the regions of high electron density and bonded electrons, follow these steps:
1. Count the number of regions around the central atom where there is electron density. This includes both lone pairs and shared pairs.
In NF2-, there are 3 regions of high electron density due to the two bonded pairs (F-N-F) and one lone pair on nitrogen.
2. Count the number of electrons involved in bonding (bonded electrons).
Since each bond consists of two electrons, and there are two bonds (F-N-F), we have 2 * 2 = 4 bonded electrons.
So, NF2- has 3 regions of high electron density and 4 bonded electrons.
To determine the electron geometry and the molecular geometry of a molecule like NF2-, we can use the valence shell electron pair repulsion (VSEPR) theory.
First, let's start by finding the total number of valence electrons in NF2-. Nitrogen (N) is in Group 5A, so it has 5 valence electrons. Fluorine (F) is in Group 7A, so each fluorine atom has 7 valence electrons. The negative charge on the molecule indicates an additional electron, so we need to add one more electron to the total. Therefore, the total number of valence electrons is:
N - 5 valence electrons
F - 7 valence electrons (x2 since there are two fluorine atoms)
Negative charge - 1 electron
Total = 5 + 7(2) + 1
Total = 21
Next, let's determine the electron geometry by using the VSEPR theory. Electron geometry is based on the arrangement of electron pairs around the central atom, including both bonding and lone pairs.
In NF2-, the central atom is nitrogen (N), and there are two fluorine (F) atoms bonded to it. So, we have three regions of electron density around the central atom: one from the lone pair on nitrogen and two from the fluorine atoms.
The arrangement of these regions of electron density is trigonal planar. This means that the electron geometry of NF2- is trigonal planar.
Now, let's determine the molecular geometry of NF2-. Molecular geometry considers only the arrangement of bonded atoms around the central atom, not the lone pairs.
In NF2-, since there are two bonded electron pairs (bonded with fluorine) and one lone pair, the molecular geometry is bent or V-shaped. The lone pair pushes the bonding pairs slightly closer together, resulting in a bent molecular shape.
In summary:
- NF2- has a trigonal planar electron geometry due to the three regions of electron density around the central nitrogen atom.
- NF2- has a bent or V-shaped molecular geometry due to the two bonding pairs and one lone pair of electrons.