Calcium is an alkaline earth metal that, being reactive, forms a dark oxide nitrate layer when exposed to air. Let us read about some properties of calcium in the article.
Calcium has an electronegativity of 1.00 on Pauling’s scale. Calcium (Ca) belongs to the s-block of the periodic table having atomic number 20. It has similar chemical properties like strontium and barium. Being a metal, its electronegativity is less than non-metals. Ca oxidation state vary from +1 to +2.
We will learn some useful properties of Ca, like ionization energy and electronegativity, and how its properties vary from other periodic table elements.
Calcium ionization energy
Calcium generally shows 1st, 2nd and 3rd ionizations though higher ionizations are also possible but the energy required for them is very large. The electronic configuration for Ca is 1s2 2s2 2p6 3s2 3p6 4s2.
- The ionization energy for the 1st ionization is 589.8 kJ/mol respectively. The removal of electrons for 1st ionization will occur from 4s orbital.
- The ionization energy for the 2nd ionization is 1145.4 kJ/mol and electron is removed from 4s orbital.
- The 3rd ionization will take place from 3p orbital and the ionization energy required is 4912.4 kJ/mol.
- As the third ionization will take place from 3p orbital which being fully-filled, is very stable and that is why an immense amount of energy is required in the case of 3rd ionization.
Calcium ionization energy graph
The graph for the 1st, 2nd and 3rd ionization energy of Ca is shown below:
From the above graph, it is evident that there is a sudden increase in the ionization energy of the ionization because the 3rd electron is to be removed from the 3p orbital which is fully-filled and is highly stable.
Calcium electronegativity
On Pauling’s scale, the electronegativity of Calcium is 1.00. It has lower electronegativity as it belongs to alkaline earth metals which tends to shift the electron pair towards the more electronegative atom.
- The electronic configuration of Ca is [Ar] 4s2 which is fully-filed and does not require any electron to get stable.
- The size of Ca is big enough and that is why the nucleus does not tightly hold the outer electrons.
Calcium and fluorine electronegativity
The electronic configuration of fluorine is [He] 2s2 2p5. Let us see how its electronegativity differs from calcium.
| Electronegativity of Ca | Electronegativity of F | Reason |
|---|---|---|
| 1.00 | 3.98 | The electronegativity of F is very high compared to Ca as F belongs to no-metals which has a greater tendency to get stabilised by gaining electrons rather than losing. Also, the size of F is very small and electrons are strongly held in the atom due to heavy nuclear force. |
Calcium and chlorine electronegativity
On Pauling’s scale, the electronegativity of the chlorine atom is 3.16 and that of Ca is 1.00. The electronic configuration of Cl is [Ne] 3s2 3p5. This will help us understand the difference in electronegativity of Cl and Ca using the table below.
| Electronegativity of Ca | Electronegativity of Cl | Reason |
|---|---|---|
| 1.00 | 3.16 | Cl has the third highest electronegativity in the periodic table as it is a halogen which generally has higher electron affinity. That is why Ca electronegativity is lower than Cl. |
Oxygen and calcium electronegativity
The electronic configuration of Oxygen is [He] 2s2 2p4 and it has an electronegativity of 3.44 on Pauling’s scale. The table below shows the variation between the electronegativity of O and Ca.
| Electronegativity of O | Electronegativity of Ca | Reason |
|---|---|---|
| 3.44 | 1.00 | O is deficient of two electrons to complete its octet and be stabilised and that is why it has a higher tendency to shift the electron pair towards it and therefore it is a highly electronegative element. |
Calcium and sulfur electronegativity
The electronic configuration of sulfur is [Ne] 3s2 3p4. It has an electronegativity of 2.58 on Pauling’s scale. Let us understand the difference between the electronegativities of Ca and S.
| Electronegativity of Ca | Electronegativity of S | Reason |
|---|---|---|
| 1.00 | 2.58 | S is a chalcogen that shows higher electronegativity but is still less electronegative than neighbouring halogens. That is why Cl is less electronegative than S. |
Calcium and potassium electronegativity
Potassium electronegativity has a value of 0.82 on Pauling’s scale and its electronic configuration is [Ar] 4s1. Let us see how the electronegativity of these two varies from each other.
| Electronegativity of Ca | Electronegativity of K | Reason |
|---|---|---|
| 1.00 | 0.82 | K is an alkali metal with a single electron in the outermost shell and is not very tightly held by the nucleus. Therefore, the electronegativity of K is less than Ca. |
Calcium oxide electronegativity
The electronegativity difference of Ca and O is 2.44, which is quite high, meaning the molecule will tend to attract the pair of electrons towards itself.
Calcium iodide electronegativity
Calcium iodide electronegativity is not clearly defined nor evident from the chemical formula.
Calcium carbonate electronegativity
Calcium carbonate electronegativity is difficult to measure as three atoms bonded in the chemical formula. There could be an error in measuring it through a normal process.
Conclusion:
This article concludes that Ca has an electronegativity value of 1.00 on Pauling’s scale, making it less tendency to attract the shared pair of electrons. Mostly Ca tries to make bonds with a slightly positive charge.
Read more about Energy & Electronegativity:
Hi, I am Sahil Singh. I completed my graduation in Bachelor of Science. I always have keen interest in Physics & Chemistry. I worked on my own blog for 1 year in the technology and gaming niche. I try my best to provide valuable knowledge through my articles.
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