chemistry notes on particle theory and bonding

The Particulate Nature of Matter
Kinetic Particle Theory




Strong intermolecular forces

Weaker intermolecular forces
than solids

Almost no intermolecular

Fixed lattice arrangement

No fixed arrangement; particles
can move and slide over each

Particles far apart and
move quickly

Particles vibrate in fixed
position; fixed shape and

Particles slide; fixed volume

Random movement; no
fixed shape or volume

When a solid is heated, the particles gain sufficient energy to overcome the strong
intermolecular forces. The particles eventually can slide over each other in a more random
motion- solid expands until the structure is broken at m,p.

When a liquid is heated to its b.p, the particles overcome the relatively weaker
intermolecular force to escape the liquids surface and move around in continuous rapid
motion – the liquid has boiled

In the vapor, the particles move in rapid random motion. This movement is due to the
collision of vapor particles with air particles.

When gaseous particles are heated in a closed environment, the increase in kinetic energy
causes increased collisions with other particles as well as the walls of the containerpressure increases.

States of Matter



Heat Energy



S -> L




L -> G




G -> L




L -> S




S -> G



Reverse sublimation

G -> S



Heating Curve

Brownian motion and Diffusion
1. Brownian motion:

It is the random movement of particles in a liquid or a gas caused due to collision with
smaller, invisible particles


In liquid- Pollen grains in water
In gases- Smoke in air

1. Diffusion

It is the spreading of one substance (liquid or gas) through another from a region of high
concentration to a region of low concentration due to the continuous random motion of

Evidence for diffusion:

In liquids: potassium manganate (VII) in a beaker of water

In gases: a gas jar of air and a gas jar of bromine connected

Factors that affect the rate of diffusion:

Temperature increases → rate of diffusion increases

Lower relative molecular mass→ rate of diffusion is higher

Experimental Techniques



Stopwatch or Clock


Thermomemeter (liquid in glass, thermistor or thermocouple)



Measuring Volume:




Measuring Cylinder

Gas Syringe

Critertia of Purity

Paper chromatography:

Drop substance to center of filter paper and allow it to dry

Drop water on substance, one drop at a time

Paper + rings = chromatogram.

Principle: Difference in solubility separates different pigments

Substances travel across paper at different rates which is why they separate into

Method works because different substances travel at different levels of attraction to

Stationary phase is material on which separation takes place

Mobile phase consists of the mixture you want to separate, dissolved in a solvent.

Interpreting simple chromatograms:

Number of rings/dots = number of substances

If two dots travel the same distance up the paper they are the same substance.

You can calculate the Rf value to identify a substance, given by the formula:
Rf Value= Distance moved by solvent DIVIDE BY Distance moved by solute

To make colourless substances visible, use a locating agent:

Dry paper in oven

Spray it with locating agent

Heat it for 10 minutes in oven

Assesing purity from m.p./b.p:

Pure substances have a definite, sharp m.p./b.p.

Substance+impurity has lower m.p. and higher b.p.

More impurity means bigger change


Mixture goes in a funnel with filter paper, into a flask.

Residue is insoluble and stays at top.

Filtrate goes through


Some water in the solution is evaporated so solution becomes more concentrated.

A drop is placed on a slide to check if crystals are forming.

Solution is left to cool and crystallise.

Crystals are filtered to remove solvent.

Simple Distillation

Impure liquid is heated

It boils, and steam rises into the condenser

Impurities are left behind

Condenser is cold so steam condenses to the pure liquid and it drops into the beaker

Fractional Distillation

Removes a liquid from a mixture of liquids, because liquids have different b.p.s

Mixture is heated to evaporate substance with lowest b.p.

some of the other liquid(s) will evaporate too.

A mixture of gases condense on the beads in the fractional column.

So the beads are heated to the boiling point of the lowest substance, so that substance
being removed cannot condense on the beads.

The other substances continue to condense and will drip back into the flask.

The beaker can be changed after every fraction

Seperating Mixture of Two Solids

Can be done by dissolving one in an appropriate solvent

Then filter one and extract other from solution by evaporation

If one solid is magnetic, can use a magnet e.g. sand and iron fillings


It dissolves…


Some salts, sugar

White spirit

Gloss paint


It dissolves…


Grease, nail polish


Glues, printing inks, scented substances

Choosing a Suitable Method
Method of separation

Used to separate


A solid from a liquid


A solid from a solution


A solid from a solution

Simple Distillation

A solvent from a solution

Fractional Distillation

Liquids from each other


Different substances from a solution

Atoms, Elements and Compounds
Atomic Structure and the Periodic Table

Relative charge

Mass (atomic mass)










Proton number: number of protons in an atom (and number of electrons in an atom)

Nucleon number: number of protons + neutrons in an atom.

In the periodic table

The proton number increases by 1 when you go to the right

When you go one element down, you increase proton number by 8 in the first 3
periods (transition elements not included)

Isotopes: atoms of the same elements which have the same protons number, but different
nucleon number

E.g. Carbon 12 and Carbon 14.

Two types: non-radioactive isotopes and radioactive-isotopes which are unstable
atoms that break down giving radiations

Medical use: cancer treatment (radiotherapy) – rays kill cancer cells using cobalt-60

Industrial use: to check for leaks – radioisotopes (tracers) added to oil/gas. At leaks
radiation is detected using a Geiger counter.

Electrons are arranged in electron shells.

Atoms want to have full outer shells (full set of valency electrons), this is why they react.

Noble gases have full outer shells so they have no need to react.

Electron shell structure: 2, 8, 8, 18.

More reactive elements have a greater desire to have a full outer shell, so also form more
stable compounds.

Bonding: the Structure of Matter

Element: substance that cannot be split into anything simpler, in a chemical reaction. Each
element has a unique proton number.

Mixture: two or more elements mixed together but not chemically combined

Compound: substance in which two or more different elements are chemically combined





Good conductors of heat & electricity

Poor conductors of heat & electricity (except graphite)

High m.p. and b.p.

Lower m.p. and b.p. than metals

High density

Low density

Forms basic oxides

Forms acidic oxides

Forms cations in reactions

Forms anions in reactions

Malleable and ductile
Some are magnetic

Alloy: Mixture of two or more metals or mixture of one or more metal with a non-metal, to
improve its properties

Ions and Ionic Bonds

Chemical bond formed by transfer of \overline{e}es from one atom to another

Metals lose \overline{e}es to form cations, non-metals gain \overline{e}es to form anions

Positive cations & negative anions attract to each other

Strong electrostatic force of attraction between positive cations and negative anions is
called ionic bonding



Form giant lattice

Cations and anions attract

High m.p. and b.p.

Strong bonds between ions

Don’t conduct electricity when solid

Ions can’t move

Conduct electricity when molten/aqueous

Ions can move

Usually soluble in water

Not required

Molecules and Covalent Bonds

When atoms share \overline{e}es to obtain a noble gas electron structure

Covalent bonding takes place between non-metals only

Single Bond

Double Bond

Triple Bond

2ē shared

4ēs shared

6ēs shared

(1 from each atom)

(2 from each atom)

(3 from each atom)




Silicon Dioxide

Four bonds

Three bonds

Makes up sand

High m.p.

Made of flat sheets

Each Si is bonded to 4 oxygen
atoms, and each oxygen is
bonded to 2 silicon atoms


Held together by weak forces so is soft ∴
used as a lubricant

∴ it has a high m.p. and is
hard, like diamond

Used for
cutting as is

Conducts electricity as it has one free e-

Melting point: high – structure made up of strong covalent bonds

Electrical: don’t conduct electricity – have no mobile ions or electrons, except for graphite

Strength: hard – exists in tetrahedral structure but graphite is soft

Metallic Bonding

Positive ions held together by electrons – acts like glu

Calculate the price
Make an order in advance and get the best price
Pages (550 words)
*Price with a welcome 15% discount applied.
Pro tip: If you want to save more money and pay the lowest price, you need to set a more extended deadline.
We know how difficult it is to be a student these days. That's why our prices are one of the most affordable on the market, and there are no hidden fees.

Instead, we offer bonuses, discounts, and free services to make your experience outstanding.
How it works
Receive a 100% original paper that will pass Turnitin from a top essay writing service
step 1
Upload your instructions
Fill out the order form and provide paper details. You can even attach screenshots or add additional instructions later. If something is not clear or missing, the writer will contact you for clarification.
Pro service tips
How to get the most out of your experience with
One writer throughout the entire course
If you like the writer, you can hire them again. Just copy & paste their ID on the order form ("Preferred Writer's ID" field). This way, your vocabulary will be uniform, and the writer will be aware of your needs.
The same paper from different writers
You can order essay or any other work from two different writers to choose the best one or give another version to a friend. This can be done through the add-on "Same paper from another writer."
Copy of sources used by the writer
Our college essay writers work with ScienceDirect and other databases. They can send you articles or materials used in PDF or through screenshots. Just tick the "Copy of sources" field on the order form.
See why 20k+ students have chosen us as their sole writing assistance provider
Check out the latest reviews and opinions submitted by real customers worldwide and make an informed decision.
Customer reviews in total
Current satisfaction rate
3 pages
Average paper length
Customers referred by a friend
15% OFF your first order
Use a coupon FIRST15 and enjoy expert help with any task at the most affordable price.
Claim my 15% OFF Order in Chat