# Chapter 2 Atomic Structure¶

## Example 2_1 pgno:28¶

In :
#given
w=100#gms
A=(w*6.022*10**23)/107.868
print "the number of atoms in the given amount of silver is" ,A

the number of atoms in the given amount of silver is 5.58274928616e+23


## Example 2_2 pgno:28¶

In :
from math import pi
# Initialisation of Variables
r=1.5*10**-7;#Radius of a particle in cm
rho=7.8;#Density of iron magnetic nano- particle in cm**3
#CALCULATIONS
v=(4./3.)*pi*(r)**3;#Volume of each Iron magnetic nano -particle in cm**3
m=rho*v;#Mass of each iron nano-particle in g
print "Volume of each Iron magnetic nano -particle in  cm**3:",v
print "Mass of each iron nano-particle in g:",m


Volume of each Iron magnetic nano -particle in  cm**3: 1.41371669412e-20
Mass of each iron nano-particle in g: 1.10269902141e-19


## Example 2_4 pgno:41¶

In :
from math import exp
# Initialisation of Variables
Es=1.8;#Electro negativity of Silicon from fig.2-8
Eo=3.5;#Electro negativity of Oxygen from  fig.2-8
#CALCULATION
F=exp(-0.25*(Eo-Es)**2);#Fraction covalent of   SiO2
print "Fraction covalent of   SiO2 :",round(F,3)

Fraction covalent of   SiO2 : 0.486