Electronegativity, Polarity and Intermolecular Forces

1. Define Electronegativity
2. How does electronegativity change across a period
3. How does electronegativity change down a group
4. Explain what is meant by a non-polar covalent molecule
5. Explain how polar molecules come about
6. Explain how a polar molecule such as HCl has permeant dipole dipole attraction
7. Explain how Temporary dipole-dipole/van der Waals come about.
8. The larger the ………………..  …………………. , the stronger van der Waals
9. What are the conditions needed for Hydrogen bonding.
10. Show how ammonia is bonded to a molecule of water.
11. Why does ice float on water?

1. Electronegativity is a measure of tendancy of an atom to attract a bonding pair of electrons in a covalent bond.

2. As you go across a period, electronegativity increases because its the same princple energy level so shielding is roughly the same, but the atomic charge increases, thus the force of attraction between positive nucleus and bonding pair of electrons. 

3. As you go down a group, there's an increasing number of princple energy levels so shielding increases, but the atomic charge remains the same. Therefore electronegativity decreases down…