Calcium (Ca) Orbital diagram, Electron configuration, and Valence electrons

The electron configuration of Calcium can be found using the Aufbau principle.

Aufbau Principle:

• The word ‘Aufbau’ in German means ‘building up’.
• The Aufbau rule simply gives the order of electrons filling in the orbital of an atom in its ground state.
• It states that the orbital with the lowest energy level will be filled first before those with high energy levels. In short, the electrons will be filled in the orbital in order of their increasing energies.
• For example, the 1s orbital will be filled first with electrons before the 2s orbital.

Simply understand that there are commonly four different types of subshells – s, p, d, and, f.

These subshells can hold a maximum number of electrons on the basis of a formula, 2(2l + 1) where ‘l’ is the azimuthal quantum number.

Value of ‘l’ for different subshells.

Subshells	Value of ‘l’	Maximum number of electrons, 2(2l + 1)	Number of orbitals in the subshell
s	0	2	1
p	1	6	3
d	2	10	5
f	3	14	7

So, in short, the s subshell can hold a maximum of 2 electrons(1 orbital), the p subshell can hold 6 electrons(3 orbitals), the d subshell can hold 10 electrons(5 orbitals), and the f subshell can hold at most 14 electrons(7 orbitals).

Now, the electron configuration of an atom can be built by filling the electrons in a lower energy subshell first then higher, higher, and higher.

Generally, (n + l) rule is used to predict the energy level of subshells.

n = principle quantum number

l = Azimuthal quantum number

⇒ Lower the value of (n + l) for an subshell, the lower its energy, hence, it will be filled first with electrons.

⇒ For two different subshells having same (n + l) value, then the subshell with lower value of n has lower energy.

So, all these are basics of How filling of electrons will be done in different subshells, obviously, you don’t have so much time for writing electron configuration by using so many rules.

Therefore, we have a diagonal rule for electron filling order in the different subshells using the Aufbau principle.

So, the order in which the orbitals are filled with electrons from lower energy to higher energy is – 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p < 7s < 5f < 6d < 7p and so on.

Calcium Electron configuration using the Aufbau Principle

• A Calcium atom is a neutral atom that has an atomic number of 20 which implies it has a total of 20 electrons.
• As per the Aufbau rule, the electrons will be filled into 1s orbital first then 2s, then 2p…so on.
• Now, for the electron configuration of Calcium, the first 2 electrons will go in 1s orbital since s subshell can hold a maximum of 2 electrons.
• The next two electrons will go into the 2s orbital, after that, the next 6 electrons will go into the 2p orbital since the p subshell can hold up to 6 electrons.
• The next two electrons will go into the 3s orbital, and after that, the next six electrons will go into 3p orbital, finally, the remaining two electrons will go into the 4s orbital.
• Therefore, the electron configuration of Calcium will be 1s²2s²2p⁶3s²3p⁶4s².

Calcium (Ca) Electron Configuration

Check – Electron configuration calculator to count the electron configuration for any atom

Orbital diagram for Calcium

The orbital diagram simply represents the arrangement of electrons in the different orbitals of an atom, it uses an arrow to represent the electrons, every orbital(one box) contains a maximum of 2 electrons.

There are three rules followed for constructing the orbital diagram for an atom.

(1). Aufbau’s principle:- This rule state that the lower energy orbital will be filled before the higher energy orbital, for example – the 1s orbital will fill before the 2s orbital.

(2). Hund’s rule:- This rule state that each orbital of a given subshell should be filled with one electron each before pairing them. That means “Each orbital gets one electron first, before adding the second electron to the orbital”.

(3). Pauli Exclusion Principle:- This rule state that, no two electrons can occupy the same orbital with the same spin. That means “One must be spin up (↑) and one must be spin down (↓)”.

If you understand the above rules then constructing the orbital diagram or orbital notation for Calcium is super easy.

Basics of Orbital diagram:-

There are different types of orbitals – s, p, d, and, f. These orbitals contain a number of boxes that can hold a number of electrons. Let’s see.

Each box will hold a maximum of 2 electrons with opposite spin.

• S orbital contains 1 box that can hold a maximum of 2 electrons.
• P orbital contains 3 boxes that can hold a maximum of 6 electrons.
• D orbital contains 5 boxes that can hold a maximum of 10 electrons.
• F orbital contains 7 boxes that can hold a maximum of 14 electrons.

The orbital diagram will also be filled with the same order as described by the Aufbau principle. (1s < 2s < 2p < 3s……and so on.)

Also check –

• Orbital diagram calculator
• Orbital diagram for all elements in the periodic table

What is the Orbital diagram for Calcium?

We know the electron configuration of Calcium is 1s²2s²2p⁶3s²3p⁶4s², now for drawing its orbital diagram, we need to show its electrons in form of an arrow in different boxes using Hund’s and Pauli’s exclusion rule.

• The orbital diagram of Calcium contains 1s orbital, 2s orbital, 2p orbital, 3s orbital, 3p orbital, and 4s orbital. 1s orbital contains 1 box, 2s orbital also contains 1 box, 2p orbital contains 3 boxes, 3s orbital contains 1 box, 3p orbital contains 3 boxes, and 4s orbital contains 1 box.
• Calcium has a total of 20 electrons and one box can hold up to two electrons.
• Therefore, the first two electrons will go into the 1s orbital, the next two will go into the 2s orbital, and after that, the next six electrons will go into the 2p orbital, since, the 2p orbital has 3 boxes.
• After that, the next two electrons will go into the 3s orbital, and the next six electrons will enter the 3p orbital. Now, the 3p orbital is full.
• Therefore, the remaining two electrons will go in the 4s orbital.

Calcium Orbital diagram

Electron configuration Vs Orbital diagram for Calcium

The main difference between the orbital diagram and electron configuration is an orbital diagram shows electrons in form of arrows whereas an electron configuration shows electrons in form of numbers. Also, the orbital diagram shows details on the spin of electrons whereas the electron configuration doesn’t show it.

Both these follow the Aufbau principle (Diagonal rule).

Also Read:–

• How to find the Electron configuration for any elements?
• How to draw the Orbital diagram for an atom?

Electron configuration for Calcium via Bohr model (Orbit)

Bohr model describes the visual representation of orbiting electrons around the small nucleus. It used different electron shells such as K, L, M, N…so on.

These electron shells hold a specific number of electrons that can be calculated via the 2n² formula where n represents the shell number.

Electron shells	Shell number (n)	Max. number of electrons (2n2)
K	1	2
L	2	8
M	3	18
N	4	32

So, K is the first shell or orbit that can hold up to 2 electrons, L is the 2nd shell which can hold up to 8 electrons, M is the third shell that can hold up to 18 electrons, and N is the fourth shell that can hold up to 32 electrons.

Now, Calcium has an atomic number of 20 and it contains a total number of 20 electrons. Hence, 2 electrons will go in the first shell(K), 8 electrons will go in the second shell(L), the next eight electrons will go in the third shell(M), and the remaining two electrons will go in the fourth shell(N).

Therefore, the electrons per shell for Calcium are 2, 8, 8, 2 hence, we can say, based on the shell, the electronic configuration of the Calcium atom is [2, 8, 8, 2].

Also check – How to draw Bohr model of Calcium atom

Calcium Valence electrons

Valence electrons are the outermost electrons present in the outermost shell of an atom. They have more energy, hence, they are part of most chemical reactions.

We can find valence electrons of an atom either by knowing its periodic group number or its electron configuration. Both these ways are super easy.

Finding Calcium Valence electrons through the Group number

For neutral atoms, the valence electrons of an atom will be equal to its main periodic group number. However, for transition metals, the process of finding valence electrons is complicated.

Now, for determining the valence electron for the Calcium atom, look at the periodic table and find its Group number. The group number can be found from its column on the periodic table.

So, the number of valence electrons in Calcium is 2. Since it belongs to Group 2nd in the Periodic table.

Finding Calcium Valence electrons through the Electron configuration or Bohr model

We know, the electron configuration of the Calcium atom is 1s²2s²2p⁶3s²3p⁶4s², and valence electrons are those electrons found in the outer shell of an atom.

This electron configuration of Calcium shows that the outer shell of Calcium has 2 electrons(4s²), hence, the number of valence electrons in the Calcium atom is 2.

Also, we know, the electron configuration of Calcium, based on the shells is [2, 8, 8, 2], which means, that two electrons are present in the first shell, eight electrons are present in the 2nd shell, eight electrons are present in the third shell, and two electrons in the fourth shell or outer shell.

Hence, the electrons found in the 4th shell of the Calcium atom are its valence electrons because it is the outermost shell also called the valence shell.

The 4th shell or outer shell of the Calcium atom contains 2 electrons, therefore, the number of valence electrons in the Calcium atom is 2.

Check – Valence electron calculator to calculate the number of valence electrons for any atom

Electron configuration, Valence electrons, and Orbital diagram of Calcium in tabular form

Name of atom	Calcium (Ca)
Number of electrons	20
Number of electrons per shell	[2, 8, 8, 2]
Number of valence electrons	2
Electron configuration	1s22s22p63s23p64s2 or [Ar] 4s2
Orbital diagram	Consists of six orbitals – 1s, 2s, 2p, 3s, 3p, and 4s.

Also read:

• Nitrogen orbital diagram and electron configuration
• Oxygen orbital diagram and electron configuration
• Carbon orbital diagram and electron configuration
• Fluorine orbital diagram and electron configuration
• Neon orbital diagram and electron configuration
• Boron orbital diagram and electron configuration
• Sodium orbital diagram and electron configuration
• Magnesium orbital diagram and electron configuration
• Aluminum orbital diagram and electron configuration
• Silicon orbital diagram and electron configuration
• Phosphorous orbital diagram and electron configuration
• Sulfur orbital diagram and electron configuration
• Chlorine orbital diagram and electron configuration
• Argon orbital diagram and electron configuration
• Potassium orbital diagram and electron configuration
• Beryllium orbital diagram and electron configuration
• Lithium orbital diagram and electron configuration

FAQ

What are the Ground state and Excited-state Electron configurations of Calcium? There is a simple difference between Ground state and Excited-state configuration. The ground state configuration of an atom is the same as its regular electron configuration in which electrons remain in the lowest possible energy. So, the ground-state electron configuration for the Calcium atom is 1s22s22p63s23p64s2. The excited-state configuration of an atom is different from the regular configuration of an atom, this occurs, when an electron is excited and jumps into a higher orbital. The excited-state electron configuration for Calcium is 1s22s22p63s23p64s14p1.

What is the shorthand electron configuration of Calcium? The shorthand electron configuration for the Calcium atom is [Ar] 4s2. ∴ [Ar] electron configuration is 1s22s22p63s23p6.

Which element has the 1s22s22p63s23p64s2 Electron configuration? Element with electron configuration 1s22s22p63s23p64s2 is Calcium (Ca) that has the atomic number of 20.

How many valence electrons does Calcium have? The Calcium atom has 2 valence electrons in its outermost or valence shell. Calcium is belonged to group 2nd and has the atomic number of 20.

What is the orbital diagram for Calcium (Ca)? The orbital diagram for Calcium is drawn with 6 orbitals. The orbitals are 1s, 2s, 2p, 3s, 3p, and 4s. The Calcium orbital diagram contains 2 electrons in the 1s orbital, 2 electrons in the 2s orbital, the six electrons in the 2p orbital, the two electrons in the 3s orbital, and the next six electrons in the 3p orbital, and the remaining two electrons will go in 4s orbital. The orbital diagram for a ground-state electron configuration of a Calcium atom is shown below-

What is the electron configuration of the Ca2+ ion? We know, in general, the electron configuration of Calcium (Ca) is 1s22s22p63s23p64s2. Now, in the Ca2+ ion, the positive charge means, Calcium loses two electrons. Therefore, to write the electron configuration of the Ca2+ ion, we have to remove two electrons from the configuration of Calcium (Ca). ∴ The resulting electron configuration for the Calcium ion (Ca2+) will be 1s22s22p63s23p6. It resembles the configuration of the nearest inert gas i.e Argon.

Properties of Calcium

• It appears as dull gray, silver; with a pale yellow tint.
• It has a boiling point of 1484 °C and a melting point of 842 °C.
• It has an FCC crystal structure.
• It is the fifth most abundant element in Earth’s crust.
• It can form a dark oxide-nitride layer when exposed to air because of its reactive nature.

Summary

• The electron configuration of Calcium in terms of the shell or orbit is [2, 8, 8, 2].
• The ground-state electron configuration of the Calcium (Ca) atom is 1s²2s²2p⁶3s²3p⁶4s². And for the excited state, it is 1s²2s²2p⁶3s²3p⁶4s¹4p¹.
• The shorthand electron configuration for Calcium is [Ar] 4s².
• The electron configuration for Calcium ion (Ca²⁺) is 1s²2s²2p⁶3s²3p⁶.
• The number of valence electrons available for the Calcium atom is 2. Calcium is situated in Group 2nd and has an atomic number of 20.
• The first shell of Calcium has 2 electrons and the outer shell or valence shell of Calcium has also 2 electrons, hence, the number of valence electrons in the Calcium atom is 2.
• The orbital diagram for Calcium is drawn by following three principles – the Aufbau principle, Hund’s principle, and Pauli’s exclusion principle.
• The Calcium orbital diagram comprises six orbitals. The six orbitals are 1s, 2s, 2p, 3s, 3p, and 4s.
• The first two electrons will go in the 1s orbital, the next two in the 2s orbital, the next six in the 2p orbital, the next two electrons in the 3s orbital, the next six electrons in the 3p orbital, and the remaining two electrons in 4s orbital.