How to Find the Valence Electrons for PH3 (Phosphine)?
The total number of electrons in the last orbit of an element is called the valence electrons of that element. Two or more elements combine to form compounds.
The valence electrons of a compound are the sum of the total valence electrons of each element in that compound. Phosphine consists of two atoms. One is a phosphorus atom and the other is a hydrogen atom.
The valence electrons of phosphine are the sum of the total valence electrons of phosphorus and hydrogen in the compound PH3. The phosphine compound has a total of eight electrons in the last orbits of phosphorus and hydrogen.
Hence, the total number of valence electrons in phosphine is eight. To determine the valence electrons of a compound, the number of valence electrons in each element of the compound must be known.
This article discusses in detail how to determine the valence electrons of phosphine very easily. Hopefully, after reading this article you will know more about this topic.
How to easily determine the number of valence electrons of PH3?
The symbol form of phosphine is PH3. To determine the valence electrons of PH3, it is first necessary to know the valence electrons of the hydrogen and phosphorus atoms.
To determine the valence electrons of phosphine we have to follow two steps. It is shown below:
Step 1: Determine the valence electrons of phosphorus and hydrogen atoms
The atomic number of phosphorus is 15. So its total number of electrons is fifteen. The electron configuration of phosphorus shows that it has five electrons in its last orbit.
We already know that the electrons in the last orbit of an element are the valence electrons of that element. Therefore, the valence electrons of phosphorus are five.
On the other hand, the atomic number of hydrogen is 1. So its total number of electrons is one. The electron configuration of hydrogen shows that it has an electron in its last orbit. Therefore, the valence electrons of hydrogen are one.
Step 2: Determine the total number of valence electrons in the phosphine compound
Phosphine is a compound. It is composed of one phosphorus atom and three hydrogen atoms.
Therefore, adding the valence electrons of one phosphorus atom and the valence electrons of three hydrogen atoms can easily determine the valence electrons of phosphine.
Mathematical Analysis:
PH3
= 5 + (1×3)
= 8
Phosphorus (P) | Hydrogen (H) | Phosphine (PH3) |
5 | 1 | 8 |
From the above mathematical analysis, we can see that the total number of electrons in the outermost orbit of phosphine is eight. Therefore, the valence electrons of phosphine are eight.
Why do you need to know the valence electrons of an element?
In addition to knowing the number of electrons of an element, it is also necessary to know the number of valence electrons of that element. The number of valence electrons of an element carries important properties of that element.
Many important properties of elements and compounds can be determined by valence electrons. Some important features are mentioned below:
- Determining the element’s position in the periodic table
- Determining the number of groups of elements in the periodic table
- Determining Valency
- Lewis dot formation
- Determination of the molecular structure of the compound
- Determination of bond pairs and non-pair electrons of compounds
Valence electrons are related to the characteristics of a compound. So we need to know the valence electrons of all the elements to determine the properties of compounds.