Anomalous Behaviour of First Element Of A Group: Detailed Study

First Element

The 1st element on the periodic table is hydrogen that has unique properties. 75% of matter in this universe has this element. Since it is present in all molecules of life, it is said that life cannot exist without hydrogen. 

Being part of group 1 in the periodic table, hydrogen shows different characteristics than other members of the group. Most often the characteristics of the first element are different from other members of the same group. 

First Radioactive Element In Periodic Table

Polonium is the first radioactive element in the periodic table. It is a rare natural element and semimetal in nature with silvery grey colour. It is an alpha emitter that produces alpha particles and is used in the form of thin sheets over stainless steel discs.  

Anomalous Behaviour Of First Element Of A Group

The first element of groups 1 and 2 and that from groups 13-17 shows different properties than other members of the respective groups. This is due to their atomic number and the absence of one electron orbital. It is also due to their small size, higher ionization enthalpies, higher charge to radius ratio, etc. 

• The elements in the s-block and p-block are called main groups or representative elements
• The p-block atoms have a smaller radius than the atoms in the s or d blocks. These smaller radii cause their electronegativity to be higher. This higher electronegativity enables them to form relatively stronger hydrogen bonds. Eg. N, F, O
• Elements such as carbon, nitrogen and oxygen are different from other elements due to their pπ–pπ multiple bonds. The other members such as Si, P, S, do not form these bonds because their atomic orbitals (3p) are larger and cannot achieve this overlapping
• The valency of the p-block elements is limited to a maximum of 4. At the same time, a higher coordination number is reachable for the other compounds of the heavier elements
• Members of the p block have a higher chance of forming pi bonds as compared to the other members of their respective families
• Their atomic orbitals are larger in size so elements such as oxygen, nitrogen, and carbon can form pi bonds with each other and with other atoms
• The elements in the p block usually have higher melting and boiling points than other members of their group. Their higher electronegativity forms help them make stronger hydrogen bonds, which is one of the strongest bonds, making it difficult to break under normal conditions
• Oxygen is diatomic in nature while the other members of its group are available in a solid-state
• Oxygen is non-metallic and is also paramagnetic while the other elements are diamagnetic
• Nitrogen exists in gaseous form while other members of its group are all solids
• When nitrogen is in a diatomic state, the other elements in its group are tetratomic
• In the case of fluorine, it is the most reactive element in its group. It exhibits negative oxidation whereas other members of the group show a positive oxidation state