How to Find the Valence Electrons for Cobalt (Co)?
The 27th element in the periodic table is cobalt. The element of group-9 is cobalt and its symbol is ‘Co’. Cobalt is a transition element. Therefore, the valence electrons of cobalt are determined differently.
The last shell of a cobalt element has only two electrons but its valence electrons are not two. This article discusses in detail how to easily calculate the number of valence electrons in cobalt. Hopefully, after reading this article you will know in detail about this.
What are the valence electrons of cobalt?
The valence electron is the total number of electrons in the last orbit. The 1st element in group-9 is cobalt and it is the d-block element. The elements in groups 3-12 are called transition elements.
But in the case of transition elements, the valence electrons remain in the inner shell(orbit). This is because the electron configuration of the transition elements shows that the last electrons enter the d-orbital.
The electron configuration of cobalt shows that the last shell of cobalt has a total of two electrons.
However, the electron configuration for cobalt in the Aufbau method shows that its last electrons(3d7) have entered the d-orbital.
The valence electrons determine the properties of the element and participate in the formation of bonds.
The electrons of the d-orbital participate in the formation of bonds. So, to determine the valence electrons of a transition element, the last shell electrons have to be calculated with the d-orbital electrons.
How do you calculate the number of valence electrons in a cobalt atom?
The valence electrons have to be determined by following a few steps. The electron configuration is one of them. It is not possible to determine the valence electrons without electron configuration.
Knowing the electron configuration in the right way, it is very easy to determine the valence electrons of all the elements.
The valence electrons of the transition element cannot be determined according to Bohr’s atomic model. This is because the valence electrons of the transition elements are located in the inner shell.
However, the valence electrons of the transition element can be easily determined according to the Aufbau principle. Now we will learn how to determine the valence electron of cobalt(Co).
Step-1: Determining the total number of electrons in cobalt
1st we need to know the total number of electrons in the cobalt atom. To know the number of electrons, you need to know the number of protons in cobalt.
To know the number of protons, you need to know the atomic number of the cobalt element.
To know the atomic number we need to take the help of a periodic table. It is necessary to know the atomic number of cobalt elements from the periodic table.
The atomic number is the number of protons. And electrons equal to protons are located outside the nucleus.
That is, we can finally say that there are electrons equal to the atomic number in the cobalt atom. From the periodic table, we see that the atomic number of cobalt is 27. That is, the cobalt atom has a total of twenty-seven electrons.
Step-2: Need to do electron configuration of cobalt
Step 2 is very important. In this step, the electrons of cobalt have to be arranged. We know that cobalt atoms have a total of twenty-seven electrons.
The first two electrons enter the 1s orbital and the next two electrons enter the 2s orbital. The next six electrons enter the 2p orbital.
The p-orbital can have a maximum of six electrons. So, six electrons enter the 2p orbital. The next eight electrons enter the 3s and 3p orbitals. The 3p orbital is now full, so the two electrons enter the 4s orbital.
We know that a d-orbital can have a maximum of ten electrons. Therefore, the remaining seven electrons enter the d-orbital. Therefore, the cobalt electron configuration will be 1s2 2s2 2p6 3s2 3p6 3d7 4s2.
Step-3: Determine the valence shell and calculate the total electrons
The third step is to diagnose the valence shell. The last shell after the electron configuration is called the valence shell.
The total number of electrons in a valence shell is called valence electrons. However, the valence electrons of the transition elements are located in the inner shell.
For the transition element, the valence electron has to be determined by adding the total electrons of the d-orbital to the electron in the last shell of the atom.
The last shell of cobalt has two electrons and the d-orbital has a total of seven electrons. Therefore, the valence electrons of cobalt are nine.
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How many valence electrons does cobalt ion(Co2+, Co3+) have?
The elements that have 1, 2, or 3 electrons in the last shell donate the electrons in the last shell during bond formation. The elements that form bonds by donating electrons are called cation.
There are two types of cobalt ion. The cobalt atom exhibits Co2+ and Co3+ ions. The cobalt atom donates two electrons in the 4s orbital to form a cobalt ion(Co2+).
Co – 2e– → Co2+
Here, the electron configuration of cobalt ion(Co2+) is 1s2 2s2 2p6 3s2 3p6 3d7.
The electron configuration shows that cobalt ion(Co2+) has three shells and the last shell has fifteen electrons(3s2 3p6 3d7).
In this case, cobalt ion(Co2+) has a total of fifteen valence electrons. Again, the cobalt atom donates two electrons in the 4s orbital and an electron in the 3d orbital to convert cobalt ion(Co3+).
Co – 3e– → Co3+
Here, the electron configuration of cobalt ion(Co3+) is 1s2 2s2 2p6 3s2 3p6 3d6.
This electron configuration shows that cobalt ion(Co3+) has three shells and the last shell has fourteen electrons. So in this case, the valence electrons of the cobalt ion(Co3+) are fourteen.
How to determine the valency of cobalt?
The ability of one atom of an element to join another atom during the formation of a molecule is called valency(valence). There are some rules for diagnosing valency.
The number of electrons in an unpaired state in the last orbital after the electron configuration of an atom is called the valency of that element.
The oxidation states of cobalt are +2 and +3. The oxidation state of cobalt +2 has been used in the Cobalt(II) oxide(CoO). The valency of cobalt in this compound is 2.
On the other hand, The oxidation state of cobalt +3 has been used in the Cobalt(III) oxide(Co2O3). The valency of cobalt in this compound is 3. The oxidation states of cobalt(Co) depend on the bond formation.
FAQs
How many valence electrons does cobalt have?
Ans: Nine valence electrons.
What is the valency of cobalt?
Ans: The valency of cobalt is 2 and 3. The oxidation state of cobalt +2 has been used in the Cobalt(II) oxide(CoO). The valency of cobalt in this compound is 2. On the other hand, The oxidation state of cobalt +3 has been used in the Cobalt(III) oxide(Co2O3). The valency of cobalt in this compound is 3.
What is the configuration for the valence electrons in cobalt’s electron configuration?
Ans: The configuration for the valence electrons in cobalt’s electron configuration is [Ar] 3d7 4s2.
How many electrons does cobalt have in its outer shell?
Ans: Cobalt has two electrons in its outer shell. The order of the number of electrons in each shell of the cobalt(Co) atom is 2, 8, 15, 2.
How to find valency of cobalt?
Ans: The number of electrons in an unpaired state in the last orbital after the electron configuration of an atom is called the valency of that element. The oxidation states of cobalt are +2 and +3. The oxidation state of cobalt +2 has been used in the Cobalt(II) oxide(CoO). The valency of cobalt in this compound is 2. On the other hand, The oxidation state of cobalt +3 has been used in the Cobalt(III) oxide(Co2O3). The valency of cobalt in this compound is 3.
Does cobalt have 2 valence electrons?
Ans: No, The valence electrons of cobalt are nine.
Why does cobalt have 9 valence electrons?
Ans: The valence electrons of the transition elements are located in the inner shell. For the transition element, the valence electron has to be determined by adding the total electrons of the d-orbital to the electron in the last shell of the atom. The last shell of cobalt has two electrons and the d-orbital has a total of seven electrons. Therefore, the valence electrons of cobalt are nine.
How many electron shells does cobalt have?
Ans: Cobalt has four electron shells.
How many valence electrons does a neutral atom of cobalt have?
Ans: A neutral atom of cobalt has nine valence electrons.