Kossel and Lewis Approach to Chemical Bonding

Amongst the following, the total number of species NOT having eight electrons around central atom in its outer most shell, is

${\mathrm{NH}}_3, {\mathrm{AlCl}}_3, {\mathrm{BeCl}}_2, {\mathrm{CCl}}_4, {\mathrm{PCl}}_5$

Why an element with $8$ electrons in the outer most shell is stable?

A molecule which cannot exist theoretically is

Explain why Octet rulle is not valid for

(1) Hydrogen and (2) lithium atom

What is the difference between di positive valence and di negative valence?

Mention the basic tendency of an atom which makes it to combine with other atoms. 

How do atoms attain noble gas configuration?

$\mathrm{HCl}$ is an electron deficient species which have less than eight electrons in the combined state.

The atoms of different elements tend to have eight electrons in their valence shell.

What is Lewis octet rule?

According to Kossel Lewis theory, every atom tries to attain octet configuration in its valence shell.

What is Kossel Lewis theory?

Which of the following compounds follows the Lewis octet rule?

Define duplet state of arrangement of atoms.

Which of the following atom tends to attain the configuration of argon by losing two electrons?

On what basis duplet set of arrangement of electrons can be defined?

Define duplet set of arrangement of electrons.

How do you define duplet set of arrangement of electrons?

Give 2 drawbacks of Kossel's Postulate.

If an element is represented by its Lewis symbols as   , then A may be