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Halogens and Noble Gases – Periodic Table

Aug 20, 2022

Key Concepts

• Valence electron

• Group

• Halogens

• Noble gas or the inert gas

Halogens and Noble Gases 



Elements are the combination of the one and only one atom. There are nearly 118 known elements. These elements have some properties, and based on the property and the size of the atoms, the elements are placed in the table form. This table is called the Periodic table. 


The Modern Periodic Table: 

The arrangement of the elements in the form of the table according to the properties of the atom and atomic number is called the periodic table. The alignment of the elements has some properties and a fixed number of electrons. The rows in the periodic table are called the periods, and the columns of the table are called the groups.  

periodic table


The penultimate column of the periodic table or the last but one column of the periodic table is column 17, and the elements of this column are called Halogens. The halogens are non-metallic. These elements are highly reactive. Only chlorine and fluorine in the list are gaseous at room temperature. The elements in the list of halogens are fluorine, chlorine, bromine, iodine, astatine.  


Bromine is liquid, whereas sodium is in the solid state. Among all the halogens, fluorine is highly reactive, and the reactive nature of halogens decreases as we go to the bottom of the periodic table. Iodine is the least reactive of all. Even though the bottom-most element in the column is astatine, it is extremely rare to find, and no one has ever found much to study the physical and the chemical properties of the element.  


Noble gasses: 

The last column of the periodic table is column 18. The elements in the last column are called noble gas elements or inert gas elements. In general, these elements are said to be the most stable elements in the periodic table and are very least reactive of all the elements in the periodic table. These elements are colorless and odorless gases at room temperature. The noble gasses in the periodic table are helium, neon, argon, krypton, xenon, radon. 

noble gases

We know, among all the inert gaseous, helium is the lightest, so this is used in filling the balloon. If a balloon is filled with helium and left free, it moves upwards into the sky. As the weight of the helium gas inside the balloon is very less, it makes the balloon float in the air. Some of the inert gasses like neon and argon are in distinctive colors, and thus, these are used in light. The smallest in size among all is helium, and the largest is radon. 


Due to their stable nature in the whole periodic table, for writing and notation of the electronic configuration of the other elements, these inert gasses are used, and the missed configuration is used.


• Elements are the combination of the one and only one type of atom.

• The arrangement of the elements in the tabular form is called the periodic table.

• The rows in the periodic table are called periods, and the columns of the periodic table are called groups.

• The 17 Group or the last but one column of the periodic table is called Halogens.

• The elements in the extreme right column of the periodic table are called noble elements or inert elements.


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