Electronic Configuration of Group 17 Elements: Principles & Sample Questions

Group-17 elements are also known as halogens, the whole group is known as the “Halogen Family”. The formula for general electronic configuration for Group-17 elements is ns²np⁵, here n represents natural numbers. The word halogen comes from Greek roots. “Halo” means salt and “genes” means producing, thus halogens are salt-producing elements. These elements when reacted with metals produce metal halide salts.

• Halogens readily react with alkali metals and alkaline earth metals to yield halide salts.
• The general electronic configuration formula for halogens is ns²np⁵.
• All Group-17 elements have seven valence electrons.

Read More: Nature of C-X Bond in Haloarenes

Key Terms: Group-17 Elements, Halogens, Halides, Metal Halides, Electronic Configuration, Salts.

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Electronic Configuration of Group-17 Elements

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The electronic configuration for Group-17 elements is ns2np5, here n represents natural numbers. Group-17 has five elements:

• Fluorine (F) 
• Bromine (Br)
• Iodine (I)
• Astatine (At) 
• Tennessine (Ts)

Out of these five elements on four elements are naturally occurring elements which are- Fluorine (F), Bromine (Br), Iodine (I) and Astatine (At), whereas Tennessine (Ts) is a synthetic element. 

Position of Halogens in Periodic Table

The electronic configuration of Group-17 elements is shown below-

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Principles for Filling Electronic Orbitals 

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The electronic configuration of an element describes the arrangement of the electrons in an orbital around the atomic nucleus. Electronic configuration helps in understanding an element's physical and chemical properties. There are certain Principles that need to be followed while filling electronic orbitals. These principles are-

• Pauli’s Exclusion Principle
• Hund’s Rule of Maximum Multiplicity 
• Aufbau Principle

Pauli’s Exclusion Principle

Pauli’s Exclusion Principle states that no two electrons in an atom can have identical values for the four of their quantum numbers. Simply, it can be said that:

• Only two electrons can occupy the same orbital.
• Two electrons in the same orbital must have opposite spins. 

Mathematically, it is given as

A(x,y) = – A(y,x)

Hund’s Rule of Maximum Multiplicity 

Hund’s Rule of Maximum Multiplicity states that in a given electron configuration, every orbital in a subshell is singly occupied before any orbital is doubly occupied. The term having maximum multiplicity is the lowest in energy. This means that electron pairing in p, d, or f orbitals cannot happen unless and until every orbital of the given subshell is singly occupied. 

Hund’s Rule of Maximum Multiplicity

Aufbau Principle

 

Aufbau Principle states that in the ground state of an atom, an orbital having a lower energy state is filled before occupying orbitals having a higher energy state. The order to fill electronic orbitals is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s and so on. 

Order of filling orbitals

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Interesting Facts About Group-17 Elements

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Some interesting facts about Group-17 elements are-

• Halogens are highly reactive elements.
• Halogens possess high electronegativities.
• Naturally halogens occur in the form of compounds and not as pure elements.
• Fluorine is the most reactive halogen and is also considered to be a deadly gas. 
• Astatine is a radioactive element.
• Astatine is utilized in medicine due to its cancer-curing properties. 
• The first halogen that was discovered is chlorine. 
• The name bromine is derived from the Greek word “bromos” meaning stench due to its foul odor. 
• Iodine is a disinfectant and is used in antiseptics.

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Things to Remember

• Group-17 elements are commonly known as Halogens.
• Group-17 has a total of five elements.
• Group-17 elements have seven electrons in their valence shells
• The general configuration of group-17 elements is ns²np⁵.
• Fluorine is the most electronegative element.
• Astatine and tennessine are radioactive elements. 
• Tennessine is the second heaviest known element.

Check Out:

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Previous Year Questions

1. A certain compound X when treated with copper sulphate solution yields a brown precipitate. On adding hypo solution, the precipitate turns white. The compound X is NEET - 1994
2. KF combines with HF to form KHF_2. The compound contains the species: BITSAT - 2005
3. Bromine is liberated, when aqueous solution of KBr is treated with: JIPMER - 1998
4. Correct order of reactivity: MET - 2004
5. The variation of the boiling points of the hydrogen halides is in the order HF>HI>HBr>HCl. What explains the higher boiling point of hydrogen fluoride ? NEET - 2015
6. Among the following, which species represents a pseudohalide? KEAM
7. The correct order of bond dissociation enthalpy of halogens is : JEE Main - 2021