chesmisty

solid particles

* incompressible
* Fixed in position
* Vibrate in their places
* Strong attraction between particles
* Fixed volume
* Fixed shape

liquid particles

* incompressible
* Vibrate
* move freely throughout the liquid but stay close together
* particles cane flow and take shape of container
* Strong attraction between particles (but not as strong as solid)
* Fixed volume

gas particles

* Compressible
* **large spaces** between gas particles and they are not stuck together
* free to move in **straight lines** until they collide with another gas particle or the side of the container
* Weak attraction between particles
* Take volume of container
* Take shape of container

particle model- change of state

When a substance is heated

* Particles have more energy and move faster
* Solid particles can vibrate out of position ie melt
* Liquid particles move faster and separate ie evaporate

When a substance is cooled

* Particles have less energy and move slower 
* Gas particles slow down and get closer together ie condense.
* Liquid particles slow down and form an ordered structure ie freeze/solidify

particle model- Expansion

* Substance is heated, makes particles move faster and take more space but not enough energy for change of state


* When the temperature increases, the particles vibrate faster, pushing each other apart.

particle model- contraction

* Substance is cooled, makes particles slow down and takes less space but not enough for a change of state


* When the temperature decreases, particles vibrate more slowly, allowing them to be packed close together.

particle model- dissolving

* When a substance dissolves, the solute particles are distributed evenly throughout the solvent particles

Solution

mixture of solute dissolved in solvent. Solutions may be transparent or coloured.

Solution = solute + solvent

Solute

substance that is dissolved in the solvent to form a solution.

Solvent

substance in which the solute dissolves in to form a solution.

particle model- diffusion

* The movement of gases or liquids spreading out in another gas or liquid


* Given time, if two liquids are mixed together, their particles will **diffuse** and mix evenly without stirring. The same occurs when two gases are mixed. 
* Increasing temperature speeds up diffusion

atom

* smallest indivisible particle of matter
* Made up of protons, neutrons and electrons

element

* pure substance made up of only one type of atom

molecule

* two or more atoms bonded together.
* These can be the same type of atom or different types

compound

* pure substance made up of two or more different elements (types of atoms)
* The elements in a compound are chemically bonded together.

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Mixture

* combination of two or more pure substances


* can be separated

periodic table- periods

* rows across the periodic table
* there are 7 periods

periodic table- groups

* columns down the periodic table
* There are 18 groups

periodic table-metals, non-metals and metalloids

* **Metals- left side of the table**
* **Non-metals on the right side of the table**
* **Metalloids- in between them**

Metals

* Shiny (lustrous)


* Hard 
* High melting and boiling points
* Good conductors of heat and electricity
* Mainly solid at room temperature
* Malleable - shape them
* Ductile -make wires

Non-metals

* Dull
* Soft
* Brittle
* Low melting and boiling points
* Poor conductors of heat and electricity
* Solids, liquid and gases at room temperature

metalloids

Have properties of both metals and nonmetals

Monatomic elements

* elements containing only one type of single atom
* only six, which are all noble gases (helium, neon, krypton, xenon, argon, radon – oganesson ??)

Molecular elements

* clusters of two or more of the same atom bonded (joined) together
* examples- oxygen O2, Nitrogen N2, bromine Br2

Crystal lattices

* grid-like structures that repeat the same arrangement of atoms
* There are two main types: metallic ( lead, copper) and non-metallic ( graphite, diamond)

Physical changes

*  does not produce new substances
* Identifying a physical change
* Changes in shape or form
* Expands (gets bigger)
* Contracts (gets smaller)
* Change in state (solid, liquid or gas)
* Mixing with another substance 

**Chemical change**

* produce new substances
* Identifying a chemical change
* A ***colour*** change
* A ***gas*** is produced- smell, bubbles, smoke
* A ***precipitate*** (solid) forming
* ***Energy being released or absorbed. released -in the form of heat, light or both- exothermic. Absorbed- cause surroundings to cool- endothermic.***

chemical reaction

* Show the “before” and “after” of a chemical change
* Start with reactants - reactants react to produce products
* **Reactants → products**

*Example:*

\
hydrogen gas + oxygen gas → water

Reactants: hydrogen gas + oxygen gas

Products: water