9 Facts Boron Electronegativity & Ionization Energy

Boron is a group of 13th non-metal elements in the periodic table having an atomic mass of 10.811 u. Let us know some important property about boron.

Boron has an electronegativity of 2.04 which is almost the same as hydrogen although is far from H atom. Being a non-metal element it has a higher electronegativity than other metals and other non-metals too.  Boron has two allotropes; one is α, β – rhombohedral, and β tetragonal, and both are different in crystal.

Boron appears as a dark, crystalline, brittle, and lustrous metalloid but in its amorphous form, it exists as a brown powder. In this article, we should learn the electronegativity property and ionization energy and comparison of electronegativity between boron and other elements in detail with proper explanation.

1. Why boron has high electronegativity?

Boron has high electronegativity on the Pauling scale due to the following reason,

  • Due to its higher attraction of sigma electrons present in p as well as s orbital.
  • Boron is placed closer to groups 16 and 17th elements which are most electronegative in the periodic table
  • The size of boron is very small and it can accumulate only five electrons so the charge density of the nucleus is very high

2. Boron and hydrogen electronegativity

Boron and Hydrogen have almost closer electronegativity values which can be explained in the following part,

Electronegativity of Boron Electronegativity of Hydrogen Reasons
2.04 2.2 H has only 1s orbital which has a higher sigma electron density due to being closer to the to the nucleus and also it can be placed in group 17th which is the the most electronegative group in the periodic table, whereas Boron has p orbital and has a lower sigma electron density.
Comparison of Electronegativity Between
Boron and Hydrogen

3. Boron and nitrogen electronegativity

The electronegativity difference between N and B is 1 and N is more electronegative than boron because,

Electronegativity of Boron Electronegativity of Nitrogen Reasons
2.04 3.04 Boron has lower electronegativity but higher electronegativity than other non-metals but N is a pnictogen element belonging to group 15 which is closer to the electronegative halogen group, so it is more electronegative than boron.
Comparison of Electronegativity Between
Boron and Nitrogen

4. Boron and oxygen electronegativity

Now come to the comparison electronegativity difference between oxygen and boron which is 1.4 because,

Electronegativity of Boron Electronegativity of Oxygen Reasons
2.04 3.44 Boron lies in group IIIA, a less electronegative group among the non-metals in the periodic table and the value is 2.04. O lies group VIA and is present in the top position also it is a chalcogen element so it has higher electronegativity,
3.44 as per the Pauling scale, and has high sigma electron affinity.
Comparison of Electronegativity Between
Boron and Oxygen

5. Boron and fluorine electronegativity

Now compare the electronegativity between boron and fluorine in the following table,

Electronegativity of Boron Electronegativity of Fluorine Reasons
2.04 3.98 B lies in group 13 which is closer to the transition metal group but the electronegativity of F is almost 4 and it is the most electronegative element in the periodic table as per the Pauling scale,as it is a halogen and present at top of group 17, so its electron affinity is very high.
Comparison of Electronegativity Between
Boron and Fluorine

6. Boron ionization energy

Generally, boron shows 1st, 2nd, and 3rd ionization, these ionization energies are 800.6, 2427.1, and 3659.7 KJ/mol respectively. Because Boron has an electronic configuration [He]2s22p1 and it releases the 1st, 2nd, and 3rd electron from its 2p orbital and 2s orbital respectively.

7.  Boron ionization energy graph

Boron’s 1st, 2nd, and 3rd ionization energy from its respective orbital shown in the below graph –

Screenshot 2022 11 27 152330
Graphical Presentation of
Ionization Energies of Boron

8. Boron and beryllium ionization energy

Boron and Beryllium belong present two different groups and both have different ionization energy which is discussed in the tabular form –

Ionization Boron Beryllium Reasons
1st 800.6
B release an electron
from its p orbital whereas
for Be, it is from the s orbital.
2nd 2427.1
2nd ionization occurs for B
from its 2s orbital which is
filled but Be also from 2s.
3rd 3659.7
3rd ionization occurs from 1s
orbital for Be which is
closer to the nucleus.
Boron and Beryllium Ionization energy

9. Boron and oxygen ionization energy

Boron is present in group 13 and O belongs to group 16 so they have different ionization values and the reasons are –

Ionization Boron Oxygen Reasons
1st 800.6
O is more electronegative so
the removal of one electron
required more energy.
2nd 2427.1
Upon 2nd ionization, O lost its
half-filled stability so it is higher
than the previous one.
3rd 3659.7
O released electron from is +2
excited state which is energetically
not favorable and required higher
amount energy.
Boron and Flourine Ionization energy

10. Boron and fluorine ionization energy

B is a group IIIA element and F is the group VIIA halogen element which is the most electronegative in the periodic table, so there must be a difference in ionization energies which can be discussed below –

Ionization Boron Fluorine Reasons
1st 800.6
F is the most electronegative atom so it has
the higher attraction of electrons and the
removal of electrons required higher energy.
2nd 2427.1
Upon 2nd ionization, it gets stability by
half-filled configuration but the electron
is removed from the +1 excited state.
3rd 3659.7
On 3rd ionization F lost its stability and also
electron was removed from the +2 excited state
so it has a larger value which is double of boron.
Boron and Oxygen Ionization energy


B is a group 13 non-metal element but the electronegativity of B is quite high than metal but lower than other non-metals. Due to higher electronegativity b has electron deficiency in its vacancy orbital and it cannot complete its octet after compound formation. So, it tries to exist in dimer by forming a  2c-3e bond in B2H6.

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