Jessybrown

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

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