WJEC AS Chemistry (1.4 Bonding)

Ions

Ions are charged particles formed when atoms lose or gain electrons.
Ions form as they are more stable (less energy) as a result forming full shells

Ionic Bonding

The strong electrostatic attraction between oppositely charged ions ( Cation and Anion)
Between a metal and non metal

Covalent Bonds

A strong attraction between a shared pars of electrons between two nuclei
Between two non metals

Inside a covalent bond

Electrons are within an orbital, electrons move around this orbitals randomly. The orbital exists between two nuclei.

Coordinate bonds

A covalent bond in which both electrons come from one of the atoms

Electronegativity

The ability of an atom to attract the electron density in a covalent bond towards itself

5 Electronegative atoms

Fluorine, Oxygen, Nitrogen, Bromine, Chlorine

Atomic Radius

Distance from nucleus to outer electrons, Bigger atomic radius the holder to hold

Shielding

The number of full shells in between the nucleus and the outer electron

Effective Nuclear Charge

The amount of protons in the nucleus and they hold on to the outer electrons.

Atomic radius vs Effective nuclear charge

AS atomic radius increase effective nuclear charge decrease. Visa versa

Type of Bonding

0 = Non-polar covalent
>0 <1.7 Polar Covalent
>1.7 Ionic

Intermolecular Bonding

Weak bonding holding the molecules together

Intramolecular Bonding

Strong bonding between atoms in the molecule.

Van der waals

All types of intermolecular force whether dipole or induced dipole. A temporary dipole is formed between the neighbouring molecule.

Movement of electrons on orbital

Electrons move randomly in the orbital and both electrons will eventually move to the same side and make a dipole charge.

Dipole-Dipole

Very strong made when Fluorine, Oxygen, Nitrogen, Bromine, Chlorine are present. They are permanent

Hydrogen bonds

Occurs when Fluorine, Oxygen, Nitrogen are directly bonded.

Bond strength

Covalent
Ionic with covalent characters
Ionic
Hydrogen Bonds
Dipole-Dipole
Van der waals

polarity of a covalent bond

Polarity mean charge, if there is a charge associated with e bond we say its polar

non-polar covalent

Polar covalent

Spends more time on side of the orbital

Soluble

Dissolve in a substance

Insoluble

Won't dissolve in a substance

Solute

Is the substance that dissolves

Solvent

What solutes dissolve in

Solution

Mixture of solvent and solute

Solubility

How well it dissolves

Intermoleuclar forces and solubility

Van der waals = Non-polar molecule (Water is polar Van der waals are weak and non polar, they do not attract

Dipole-Dipole and Hydrogen bonds = polar molecule
Both molecules are polar so there forces are attracted.q

Shapes of molecules

Electron pairs will always mutually repel each other as far away as possible

Linear, 180° - 2 pairs of electrons

e.g BeCl₂

Trigonal Planar, 120⁰ - 3 pairs of electrons

e.g BCl₃

Tetrahedral, 109.5° - 4 pairs of electrons

e.g CH₄

Trigonal Bipyramid, 90° and 120⁰ - 5 pairs of electrons

e.g PCl₅

Octahedral, 90⁰ - 6 pairs of electrons

e.g SCl₆

How to draw

1. Draw dot and cross diagram
2. Add on lone pairs and bond pairs
3. Count number of bonds to work out shape