Stage 1 Chem: Topic 2 - Combs of atoms

NOTES NOT FLASHCARD (BLURT) Materials: Metals & Ionic salts (Na/Cl, metal, non-metal) & covalent (non-metals): giant lattice & molecular

bond strength & mpt & conductivity e^-1 of 3 types of materials
Metals: high & strong & Yes(s,l) (primary Ionic bontds)
Ionic salts: high & strong (primary ionic bonds) & No(s),Yes(l,aq)
covalent (giant lattice): high & strong (primary ionic bonds) & No (s,l),Yes(graphite)
covalent (molecular comp): low & weak (secondary ionic bonds) & very strong (primary) & No(s,l,graph)

Physical Properties

Solubility in water (a polar solvent)  or cyclohexane (a non-polar solvent)

•Melting point/Boiling Point

•Electrical Conductivity as a solid

•Electrical Conductivity when molten or dissolved in water

•Softness/Hardness

What are Van der Waals Forces?

weak electrostatic forces that attract neutral molecules to one another

Describe solubility in water or cyclohexane in terms of polar and non-polar solvents

Polar substances dissolve in polar solvents (like water).
Non-polar substances dissolve in non-polar solvents (like cyclohexane).
Water molecules are polar, meaning they have a slight positive charge on one side and a slight negative charge on the other.
Cyclohexane molecules are non-polar, meaning their charge is evenly spread, so they don’t have positive or negative ends.

What is hydrogen bonding

Stronger Version of Dipole-Dipole

A special case of dipole-dipole interactions, occurring when H is bonded to N, O, or F (very electronegative atoms).
These bonds are much stronger than normal dipole-dipole forces.