Chemistry electronegativity and intermolecular forces

Electronegativity definition

The ability for atoms to attract the bonding electrons in a covalent bonds

What is the Pauling scale

The measure of electronegativity

What does electronegativity difference dictate

Bond type

How do simple molecular substances interact in polar solvents

Does not dissolves in water

How to represent a hydrogen bond on a diagram

Dashed line between H nucleus and lone pair

What can increase london forces?

The number of electrons in the molecule

If all of the atoms are in a longer and thin structure

Order of intermolecular forces in strength

London forces < permanent dipole dipole < hydrogen bonding

Are non polar substances soluble in polar solvents

No

Is a non polar substance soluble in a non polar solvent

Yes (e.g. hexane)

Why is the solubility of polar molecules are hard to predict?

Depends on the strength of the dipole

How do london forces come about?

Random movement of electrons produces a changing dipole which will induce a dipole on the neighbouring molecules. London forces are the attraction due to these instantaneous dipole.

How do permanent dipole dipole forces arise?

In a polar molecule, the permanent dipoles attract each other so the molecules form an arrangement with positive and negative charges adjacent

What are the anomalous properties of water due to hydrogen bonds

Higher B.P./M.P, high viscosity and surface tension, liquid water is more dense than ice

Why is water less dense than ice

The hydrogen bonds form a open lattice structure which is less dense than liquid structure

What elements form hydrogen bonds

H/N/O/F

Hydrogen bond definition

A strong dipole dipole interaction between a positive hydrogen nucleus and a lone pair of electrons

Symbol for dipoles

What is a polar molecule

A non symmetrical molecule with polar bonds so there is an overall dipole

Factors that affect electronegativity

Nuclear charge, atomic radius and shielding

How many hydrogen bonds does a water molecules form

2 hydrogen bonds

Why are non polar substances insoluble in polar solvents

The intermolecular forces are weaker in the substance so there will not be enough interaction between solvent and solute to dissolve

Why is a non polar substance soluble in a non polar solvent

Because the intermolecular forces interact and weaken in the simple molecular lattice, causing the solvent to move apart and allow the substance to dissolve

How does nuclear charge affect electronegativity

The more protons the stronger the attraction between the nucleus and the bonding pair

How does atomic radius affect electronegativity

Closer to the nucleus means stronger attraction between the nucleus and bonding pair

How does shielding affect electronegativity

Less shells of electrons between the nexulus and shared pair causes stronger attraction