Isotopes= a group of atoms with the same no. of protons , but different no. of neutrons
Hydrogen isotopes

The name of the second isotope is deuterium and the name of the third isotope is tritium(radioactive).The most abundant isotope is
Boron’s chemistry is not typical of its group. is group 3A (13) shows the increasing metallic character from Al to Tl.
All Boron compounds are covalent whereas the other elements in group 3A (13) form mostly ionic compounds.
Except for Boron, the other elements of group 3A (13) show increasing metallic character from Al to Tl. But Boron is a metalloid.
Compared to the other elements in group 3A, boron has a lower reactivity in chemical terms (13)
The metalloid boron (B), as well as the metals aluminium (Al), gallium (Ga), indium (In), and thallium, are all part of group 3A (or IIIA) of the periodic table (Tl). In contrast to the other members of Group 3A, the element borax primarily forms covalent connections.
To learn more about group 3A (13) refer the link:
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