The Boron Family in the Periodic Table


Group 13 Boiling point 4000oC, 4273K, 7232oF
Period 2 Melting point 2077oC, 2350K, 3771oF
Block p Relative atomic mass 10.81
Atomic number 5 Density (g cm-3) 2.34
State at 20oC Solid Key isotopes 11B
Electronic configuration [He] 2s2 2p1 CAS number 7440-42-8

Boron got its name from the Arabic word ‘buraq’ which is the name of borax. It belongs to the 13th group of the p block element. The elements of the 13th group element are boron, aluminium, gallium, indium, and thallium. They all are metallic in nature except boron which is a metalloid. All of them has 3 electrons in the outermost shell which has the electronic configuration of ns2np1. There are two oxidation states (+3 and +1) of boron family.

Boron is a non-metal but the second element is aluminium which is a metal. Gallium, indium and titanium are almost metallic in nature. Aluminium is also one of the most important members of the boron family which has an atomic number of 13 and chemical symbol is Al. It is very expensive to produce aluminium because for electrolysis of one mole of aluminium, we require 3 moles of electron and thus a huge amount of energy is used.

Do you know why aluminium does not react with water?

A protected layer of Al2O3 is formed due to which it does not react with water. This process is also called as anodising.

Gallium which has chemical formula Ga and atomic number 31 and has the second lowest melting point after mercury and it can persist in a liquid phase at larger temperature than any other substance. Gallium is very important industrially as it forms Gallium arsenide which converts light directly into electricity.

Indium is also one of the p block element with atomic number 49. Indium is also soft malleable metal just like gallium. In the acids indium is soluble but at room temperature, it does not react with oxygen. Indium is used for increasing the strength of metals and is also used in making alloys.

Thallium which has chemical formula Tl is a heavy element and is also very stable in +1 oxidation state. Even though it’s poisonous then also it is used in high-temperature superconductors.

There is a diagonal relationship between beryllium and aluminium which is that when it reacts with water both of these compounds produce hydronium ions, and one more similarity between these two is that both of them are amphoteric in nature.