Answer to Question #61190 in General Chemistry for Hajra

Question

Explain octet and duplet rule with examples?

Answer 1

According to them (duplet and octet rule), elements tend to combine with one another to attain the stable electronic configuration of the nearest inert gas (duplet or octet). Octet Rule and Duplet Rule Inert gases like neon, argon etc. do not form chemical compounds. These elements have monoatomic molecules. Octet Rule and Duplet Rule Atoms of gases like Neon and Argon have eight electrons in their valence shells. This leads to a stable electronic configuration. On this basis; G.N Lewis gave the octet rule. The Octet rule is a simple chemical rule that states, that atoms tend to combine in such a way, that they have 8 electrons in their valence shells, giving them the same electronic configuration as a noble gas Octet Rule and Duplet Rule During bond formation, only the electrons of the outermost shells play an important role. The sodium atom transfers its outermost electron to a chlorine atom and becomes a positively charged ion. When chlorine atom receives one electron, it becomes a negatively charged ion. Octet Rule and Duplet Rule The positively charged sodium ion has a total of ten electrons and eleven protons while chlorine atom has 18 electrons and 17 protons. The sodium atom achieves neon-like configuration after loosing one electron, while chlorine gets argon like configuration after gaining one electron. Octet Rule and Duplet Rule The octet rule is a very useful rule but you should also know that there are certain bonding situations where it does not apply. Certain elements like lithium and hydrogen do not attain eight electrons in their outermost valence shell. Octet Rule and Duplet Rule Lithium and hydrogen attain stability by acquiring the electronic configuration of their nearest inert gas i.e. Helium. Helium has a fully-filled outermost shell with two electrons and is stable. This is known as duplet rule. Summary Inert gases like neon, argon etc. do not form chemical compounds. Atoms of gases like Neon and Argon have eight electrons in their valence shells. The octet rule is a simple chemical rule that states that atoms tend to combine in such a way that they each have eight electrons in their valence shells, giving them the same electronic configuration as a noble gas. Lithium and hydrogen attain stability by acquiring the electronic configuration of their nearest inert gas i.e. Helium. Helium has a fully-filled outermost shell with two electrons and is stable.