Jessyqueen

Relative mass of a proton 1 Relative mass of a neutron about the same as that of a proton Relative mass of an electron 1/1840 Relative charge of a proton +1 Relative charge of a neutron 0 Relative charge of an electron -1 Neutral atoms same number of positive protons as negative electrons

Relative mass of a proton 1 . Relative mass of a neutron about the same as that of a proton Relative mass of an electron 1/1840 Relative charge of a proton +1 Relative charge of a neutron 0 Relative charge of an electron -1 Neutral atoms same number of positive protons as negative electrons Atomic (proton) number the number of protons in the nucleus of an atom

Ancient greek model of the atom Atoms are tiny solid spheres which cannot be divided. JJ Thompson Discovered the electron and developed the "plum-pudding" model of the atom plum pudding model of the atom atoms are balls of positively charge with negative electrons embedded in it

What are 'Mechanical Properties'? - Properties of materials, including strength, hardness, density, durability, toughness, malleability, elasticity and ductility What is 'bending'? - The ability to withstand forces that are attempting to bend What is 'compression'? - The resistance to forces that are trying to crush or shorten What is 'shear'? - The resistance to forces sliding in opposite directions What is 'tension'? - The resistance to forces pulling in opposite directions Wha...

First shell can hold 2 electrons 2nd and 3rd shell can hold 8 electrons no of shells = Period on the periodic table Valence electrons Outer shell electrons which are involved in reactions No of valence electrons = Group number on the periodic table Hydrogen electron structure 1 Nitrogen electron structure 2,5

Atom Smallest part of an element Element A pure substance made of only one kind of atom Compound A substance made up of atoms of two or more different elements joined by chemical bonds Mixture A combination of two or more different substances that are not joined by chemical bonds

What are the structures of an animal cell? - Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. What are the structures of a plant cell? - All structures from animal cells and cell wall, permanent vacuole and chloroplasts. What does the nucleus do? - Stores DNA and directs all cellular activities. What is the cytoplasm do? - Where most chemical reactions take place. What does the cell membrane do? - Holds the cell together and controls what goes in and out. What is the mitocho...

What are the structures of an animal cell? - Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. What are the structures of a plant cell? - All structures from animal cells and cell wall, permanent vacuole and chloroplasts. What does the nucleus do? - Stores DNA and directs all cellular activities. What is the cytoplasm do? - Where most chemical reactions take place. What does the cell membrane do? - Holds the cell together and controls what goes in and out. What is the mitocho...

Tough supporting wall of the eye - Sclera Transparent outer layer found at the front of the eye. Refracts (bends) light into the eye - Cornea Contains muscles that allow it to control the diameter of the Pupil (hole in the middle) and therefore how much light enters the eye - Iris Focuses light onto the retina - Lens Contains receptor cells sensitive to light intensity and colour - Retina Controls the shape of the lens - Ciliary Muscles and Suspensory Ligaments Carries impulses from the r...

Natural Hazard - A natural hazard is a natural process which could cause death, injury or disruption to humans, or destroy proprty or posesions. Natural disaster - A natural hzard that has actualy happened Geological hazards - Caused by kand and tectonic processes Meteorological hazards - Caused by weather and climate Factors affecting hazard risk - Urbanisation, poverty, development, climate change Tectonic plates - Slabs of the Earth's crust Continental crust - thicker and less dense ...

Name of Group 7 elements The halogens Group 7 elements have similar chemical properties because they all have 7 outer shell electrons Diatomic molecule A molecule consisting of two atoms

Formation of metal ions Atoms lose outer electrons Metals Elements that form positive ions Formation of non-metal ions Atoms gain electrons Charge on non-metal ions negative Group 1 ions charge +1 Group 2 ions charge +2 Group 6 ions charge -2 Group 7 ions charge

Metals Elements which form positive ions Non-metals Elements which do not form positive ions Metals position on periodic table on the left hand side Non-metals position on periodic table

Metal An element that forms positive ions pH of metal oxide Basic Non-metal Does not form positive ions pH of non-metal oxide Acidic Reduction in terms of oxygen Loss of oxygen Oxidation in terms of oxygen Gain of oxygen Oxidation in terms of electrons Loss of electrons

H - Hydrogen He - Helium Fe - Iron N - Nitrogen Na - Sodium F - Fluorine Li - Lithium C - Carbon CO2 - carbon dioxide

Requirements for a reaction to take place Particles must collide, with sufficient energy Activation energy Minimum amount of energy required to start a chemical reaction Reaction profile diagram A graph which shows the change in energy of a chemical reaction Products The new substances formed by a chemical change

Mixture A combination of two or more substances that are not chemically joined. Filtration Separates insoluble solids from liquids. Crystallisation The formation of crystals by cooling a saturated solution Simple distillation Used to separate a liquid from a solution

Transition elements are found In the middle block of the periodic tableRe Physical properties of transition elements Hard, high melthing points, strong and dense. Chemical properties of transition elements Slow/no reaction with oxygen, water and halogens Charges on transition metal ions Form positive ions often with the ability to form more than one ion

Ion An atom or group of atoms that has lost or gained electrons and therefore a positive or negative charge. Polyatomic ion An ion that is made of more then one atom Metal ion an atom which has lost electrons forming a positive ion Non-metal ion an atom which has gained electrons forming negative ions. Covalent bond a shared pair of electrons Molecule two or more atoms held together by covalent bonds Metallic bonding Positively charged metal ions are surrounded by delocalised outer ...

Evaluate how far the power of the executive has been undermined by constitutional reforms since 1997 PARA 1 - P1 - P1 - devolution Blair, as part of his democratising reforms, enabled referendums to be held on devolving legislative powers to Scotland, Wales and NI. This has undermined the power of the executive by granting other assemblies powers that used to be held at westminster. Westminster now has no say on certain areas of legislation in devolved assemblies. 1997 resulted in an overwh...