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solid particles

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.

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