C1

C1.1.1-Paritcles

Everything is made from matter

Matter is made from paritcles

Models are used to solve problems, making predictions and developing scientific knowledge

The particle model is used to describe the arrangement of
particles and their different states

The particle model is used to explain certain properties
of a substance

C1.1.2-Chemical and physical changes

Physical changes is a change of state

E.g. Ice melting

Reversible and no new substances made

In a physical change the particles are the same
but their arrangement and movement change

Chemical change is a change which produces new substances

It usually irreversible and creates a new substance

The particles then form in a different way

C1.1.3-Limitations of the particle model

Size

The smallest particle that make up a substance
is called an atom

The smallest atoms are helium at 62x10^-12 m
in diameter

Distance between two helium is 55x larger than
diameter of the atom

Space

To calculate ratio of an atom

Ratio= Distance between atoms
Diameter of atom

Forces

Particles are held together by electrostatic forces

Forces of attraction between positive
and negative charges

The further the particles the weaker the forces

C1.2.1-Atomic structures

Size of atoms

The size of an atom is given by its
atomic radius(half its diameter)

The length of the bond is the distance between
two joined atoms

Atomic radii and bond length is typically around
10^-10 (0.1nm)

Subtopic

Elements

Substances whose atoms have the same atoms
have the same atomic number