Boron (B) - Element 5 | Properties & Electron Configuration
What is Boron?
Boron (B) is element 5, a metalloid in period 2, group 13. Its electron configuration is 1s² 2s² 2p¹.
| Atomic Number | 5 |
| Symbol | B |
| Atomic Mass | 10.81 u |
| Category | Metalloid |
| Period | 2 |
| Group | 13 |
| Block | p |
| Electron Configuration | 1s² 2s² 2p¹ |
| Short Config | [He] 2s² 2p¹ |
| Electronegativity | 2.04 |
| Atomic Radius | 85 pm |
| Ionization Energy | 801 kJ/mol |
| Electron Affinity | 27 kJ/mol |
| Phase (STP) | Solid |
Electron Configuration
The full electron configuration of Boron is 1s² 2s² 2p¹. In noble gas shorthand, this is written as [He] 2s² 2p¹.
Boron is a p-block element in group 13, period 2.
Periodic Trends
Electronegativity: Boron has a Pauling electronegativity of 2.04. Within group 13, electronegativity generally decreases down the group.
Atomic Radius: 85 pm. Across period 2, atomic radius generally decreases left to right as nuclear charge increases.
Ionization Energy: 801 kJ/mol. Ionization energy generally increases across a period and decreases down a group.
View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.
Explore Boron on the Interactive Periodic TableRelated Topics
Aluminum (Al)
Properties of Aluminum - same group as Boron
Gallium (Ga)
Properties of Gallium - same group as Boron
Indium (In)
Properties of Indium - same group as Boron
Lithium (Li)
Properties of Lithium - same period as Boron
Beryllium (Be)
Properties of Beryllium - same period as Boron
Carbon (C)
Properties of Carbon - same period as Boron