# How many valence electrons does calcium(Ca) have?

The 20th element in the periodic table is calcium. Calcium is an alkaline earth metal and its symbol is ‘Ca’. Calcium participates in the formation of bonds through its valence electrons. This article discusses in detail the valence electrons of calcium(Ca).

## How many electrons and protons does the calcium atom have?

The nucleus is located in the center of the atom. Protons and neutrons are located in the nucleus. The atomic number of calcium(Ca) is 20. The atomic number is the number of protons.

That is, the number of protons in the calcium is 20. Electrons equal to protons are located in a circular shell(orbit) outside the nucleus. That is, the calcium(Ca) atom has a total of twenty electrons.

## What are the valence electrons of calcium(Ca)?

The 3rd element in group-2 is calcium(Ca). All the elements of group-2 are called alkaline earth metals. Therefore, calcium is an alkaline earth metal. The valence electron is the total number of electrons in the last orbit.

The total number of electrons in the last shell after the electron configuration of calcium is called the valence electrons of calcium(Ca). The valence electrons determine the properties of the element and participate in the formation of bonds.

The twentieth element in the periodic table is calcium(Ca). That is, the atom of the calcium element has a total of twenty electrons. The electron configuration of calcium shows that the last shell(orbit) of calcium has a total of two electrons.

That is, we can easily say that calcium has two valence electrons. There is an article on this site detailing the electron configuration of calcium, you can read it if you want.

## How to determine the valence electron of calcium(Ca)?

Now we will know how to easily determine the valence electron of calcium(Ca). The valence electron has to be determined by following a few steps. The electron configuration is one of them. It is not possible to determine the valence electron without electron configuration.

Knowing the electron configuration in the right way, it is very easy to determine the valence electrons of all the elements. There is an article published on this site detailing the electron configuration, you can read it if you want. However, this article briefly discusses electron configuration.

Scientist Niels Bohr was the first to give an idea of the atom’s orbit. He provided a model of the atom in 1913. The complete idea of the orbit is given there. The electrons of the atom revolve around the nucleus in a certain circular path. These circular paths are called orbit( shell). These orbits(shell) are expressed by n. [ n = 1,2 3 4 . . .]

K is the name of the first orbit(shell), L is the second, M is the third, N is the name of the fourth orbit(shell). The electron holding capacity of each orbit is 2n2.

Now,

• n = 1 for K orbit. The electron holding capacity of K orbit is 2n2 = 2 × 12 = 2 electrons.
• For L orbit, n = 2. The electron holding capacity of the L orbit is 2n2 = 2 × 22 = 8 electrons.
• n=3 for M orbit. The maximum electron holding capacity in M orbit is 2n2 = 2 × 32 = 18 electrons.

In addition to this method, electron configuration can be done through sub-orbits. The German physicist Aufbau first proposed an idea of electron configuration through sub-orbits. The Aufbau method is to do electron configuration through the sub-energy level.

These sub-orbitals are expressed by ‘l’. The Aufbau principle is that the electrons present in the atom will first complete the lowest energy orbital and then gradually continue to complete the higher energy orbital. These orbitals are named s, p, d, f. The electron holding capacity of these orbitals is s = 2, p = 6, d = 10 and f = 14.

However, valence electrons can be easily identified by arranging electrons according to the Bohr principle. Now we will learn how to determine the valence electron of calcium(Ca).

### Step-1: Determining the total number of electrons

1st we need to know the total number of electrons in the calcium(Ca) atom. To know the number of electrons, you need to know the number of protons in calcium. And to know the number of protons, you need to know the atomic number of the calcium 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 calcium(Ca) 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 calcium atom. From the periodic table, we see that the atomic number of calcium(Ca) is 20. That is, the calcium atom has a total of twenty electrons.

### Step-2: Need to do electron configuration

Step 2 is very important. In this step, the electrons of calcium(Ca) have to be arranged. We know that calcium atoms have a total of twenty electrons. The electron configuration of calcium shows that there are two electrons in the K shell, eight in the L shell, eight in the M shell, and two in the N shell(orbit).

That is, the first shell of calcium(Ca) has two electrons, the second shell has eight electrons, the 3rd shell has eight electrons and the 4th shell(last orbit) has two electrons. The number of electrons per shell of calcium(Ca) is 2, 8, 8, 2. The electron configuration of calcium(Ca) through the sub-orbit is 1s2 2s2 2p6 3s2 3p6 4s2.

### Step-3: Determining the valence shell(orbit) and calculate total electrons

The third step is to diagnose the valence shell(orbit). The last shell after the electron configuration is called the valence shell(orbit). The total number of electrons in a valence shell is called a valence electron.

The electron configuration of calcium shows that the last shell(orbit) of calcium has two(4s2) electrons. Therefore, the valence electrons of calcium(Ca) are two. In this way, the valence electrons of all the elements can be determined.

## Determination of the valency of calcium

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(valence) of that element.

The electron configuration of calcium(Ca) is 1s2 2s2 2p6 3s2 3p6 4s2. The electron configuration of calcium shows that it has two unpaired(4s2) electrons in the last orbital. Therefore, the valency(valence) of calcium is 2.

## How many valence electrons does calcium ion(Ca+2) have?

After the electron configuration, the last shell(4s2) of the calcium atom has two electrons. In this case, the valence(valency) of calcium is 2. We know the details about this. The elements that have 1, 2, or three electrons in the last shell(orbit) donate the electrons in the last shell during bond formation.

The elements that form bonds by donating electrons are called cations. That is, calcium is a cation element. Calcium(Ca) donates the electron of the last shell to form bonds and turns into calcium ions.

Ca – 2e → Ca+2

The electron configuration of calcium ions (Ca+2) is 1s2 2s2 2p6 3s2 3p6. The electron configuration of calcium ion(Ca+2) shows that calcium ion has only three shells and that shell has eight electrons (3s2 3p6). The electron configuration shows that the calcium atom has acquired the electron configuration of argon.

That is, in this case, the valence (valency) of the calcium-ion is +2. Since the last shell(orbit) of a calcium-ion has eight electrons, the valence electrons of calcium-ion(Ca+2) are eight.

## Compound formation of calcium

Calcium participates in the formation of bonds through its valence electrons. We know that the valence electrons in calcium(Ca) are two. This valence electron participates in the formation of bonds with atoms of other elements.

The electron configuration of oxygen shows that the valence electrons of oxygen are six. The calcium atom donates its valence electrons to the oxygen atom and the oxygen atom receives those electrons.

As a result, oxygen acquires the electron configuration of neon, and calcium atoms acquire the electron configuration of argon. Calcium oxide(CaO) is formed by the exchange of electrons between one atom of calcium and one atom of oxygen. Calcium oxide(CaO) is an ionic compound.