valence shell complete values

A complete third valence shell represents 18 electrons.

 This is because the third principal energy level (\(n=3\))

 contains three types of subshells, 

which hold a specific number of electrons: 

3s subshell: holds 2 electrons

3p subshell: holds 6 electrons

3d subshell: holds 10 electrons 

Adding them together (\(2+6+10\)) 

gives a total capacity of

 18 electrons. 

This can also be calculated

 using the formula \(2n^{2}\), 

where n is the shell number.

 For the third shell (\(n=3\)), 

this is \(2(3)^{2}=18\). 

Why 8 electrons is a common answer 

Many introductory chemistry courses 

use a simplified model for the first 20 elements,

 stating that the third shell is complete 

with 8 valence electrons. 

This is because the 3s and 3p subshells 

are filled, 

creating a stable octet, 

before the 3d subshell begins to fill. 

The 3d subshell has a higher energy level 

and does not begin to fill 

until after the 4s subshell is filled. 

For example, 

the noble gas argon (Ar) 

has a full valence shell

 with 8 electrons,

 even though 

the maximum capacity of 

the third energy shell

 is 18 electrons

 This is what makes argon

 stable and unreactive. 

Elements that fill the remaining 10 spots in the 3d subshell,

 like zinc (Zn), 

are known as transition metals 

and are found in the fourth row 

of the periodic table. 

AI responses may include mistakes

Atoms with 8 electrons in their valence shell  

 

 

 

have completely filled last orbitals and are therefore the most stable, as their electronic configuration is similar to that of the closest noble gas.

The number 8 is a lucky number, according to many Asian cultures. The Chinese consider the number lucky because its pronunciation bā is similar to fā, meaning wealth. Interestingly, the Beijing Summer Olympics took place on August 8th, 2008 at 8 seconds and 8 minutes past 8 pm.

The Japanese consider it a lucky number regarding the idea of prosperity, as the script for 8 in Japanese is 八, which broadens gradually, implying growing wealth.

The Significance Of “8” In Chemistry

In chemistry, 

8 isn’t a lucky number, per se, 

but, a number that indicates stability. 

The rule of 8 or the Octet rule is 

the tendency of atoms to have 

eight electrons in their valence shell.

Eight electrons in this 

outer shell 

allow atoms to 

be stable and non-reactive.

Noble gases, 

are some of the most non-reactive 

chemical elements 

one can find in nature. 

They compose the far-right section

 of the periodic table 

and are known as noble gases 

because they are 

self-sufficient! 

They have 2, 8, 18, or 36 electrons 

in their outer shell.

Atoms tend to be reactive 

when their valence shell (or outermost shell) 

is incomplete.

 To achieve a complete state 

or a closed shell, 

an atom does one of the 3 things: 

lose, gain, or share its electrons 

with other atoms.

An atom is—a nucleus

 with  number of protons

and electrons —

orbiting the same center at

Differing Radii

AS

a combination of 

several shells 

arranged in concentric circles, 

called the electronic configuration 

of the atom. 

The valence shell

 let’s begin with the basics.

What Is 

The Electronic Configuration 

Of An Atom?

The electronic configuration of an atom 

is the distribution of electrons in an atom.

 Imagine our solar system, 

with the planets revolving around the sun;

 similarly, the atom has electrons 

revolving around its central nucleus

 in distinct electron shells.

The Bohr model, 

Written up

 by the Danish physicist Niels Bohr in 1913,

 was the first model to suggest 

that electrons in an atom are contained

 in electron shells. 

This shell only allows 

a certain number of electrons 

to be a part of it.

 Another scientist took this theory forward

 and came across a unique finding 

The American physical chemist 

professor Gilbert Newton Lewis stated that,

 like the Helium atom, 

with 2 electrons in its valence shell,

 8 electrons might be arranged in successive shells,

 mimicking the corners of a cube. 

This arrangement led to 

a very stable state of atoms, 

due to their resemblance to noble gases.

The n^th shell of an electron 

will accommodate 2n² number of electrons, 

where n is 

the principal quantum number 

or the energy level.

 In quantum mechanics, 

there are 4 quantum numbers

 assigned to 

every electron in an atom 

to designate a unique state 

of the electron. 

These quantum states 

of an electron 

make up for

 the wave-like nature 

or orbital nature

 of an electron.

 This forms a part of advanced chemistry, which is beyond the scope of this article; further reading is recommended, if required/desired

So, if n=1, i.e. the first shell,

 the number of electrons will be 2 for that shell. 

For n=2, the number will be 8, and so on 

2

 8

2*3^2 = 18 

2*4^2 = 32

The shells are also known as

 K, L, M, N etc

The energy associated with valence levels

 increases 

as we move away from the nucleus

 

The shells are also known as K, L, M, N and so on. The energy associated with energy levels increases as we move away from the nucleus. The opposite charges of the electrons and the nucleus in the lower energy levels cause the electrons to be tightly bound to the nucleus. The further the electrons are from the nucleus, the more reactive they become.