Practice of coding during UT clinic [ Electronegativity values difference between elements ]

The UT clinic was unhelpful to a large extent, so I practice programming on my own without any references.

a = raw_input("Please enter the 1st Electronegativity")
b = raw_input("Please enter the 2nd Electronegativity")

try:
    a = float(a)
    if a < 0:
        print "Invalid value"
        exit()

    b = float(b)
    if b < 0:
        print "Invalid value"
        exit()

except:
    print "Please enter valid float"
    exit()

if a > b:
    c = a - b
elif b > a:
    c = b - a

if c < 0.5:
    print "Difference is " + `round(c,2)`
    print "It is Non-Polar Covalent Bond"
    print "Temporary Charges"

if c > 0.5 and c < 2.0:
    print "Difference is " + `round(c,2)`
    print "It is Polar Covalent Bond"
    print "Permanent Charges"

if c > 2.0:
    print "Difference is " + `round(c,2)`
    print "It is Ionic Bond"
    print "Permanent Charges"

Electronegativity and Types of bonds

When two atoms share electrons, a covalent bond is formed.

i.    If electrons are shared more or less equally, a non-polar covalent bond exists between the atoms (e.g. H-C).

ii.    If electrons are shared unequally, a polar covalent bond exists between the atoms (e.g. H-O).

Values of the elements

Tuesday, 19th June 2012

Slept at 10 pm last night
Today woke at 7 am to buy Egg McMuffin for Muffin

Today need study the chemical properties of water
Example:
- Why does ice cube float on water
- Why is water able to dissolve various substances like salt
- Why water has a high boiling point

Notes :
Hydrogen Bonding can only occur when H is interacting with F, N or O

To determine the polar, non-polar or ionic bond.
Need calculate the difference between the elements de elctronegativity values.