Elements/Chemical reactions

• An atom is the smallest part of an element
• An element is a substance made from only one type of atom
• Protons and neutrons are found in the nucleas and electrons are found o the shells
• A element can take 3 forms

  • Solid
  • Molecule
  • Atom
• • Every atom has 3 subtomic particals: protons, neutrons and electrons
• Only 2 electrons can go on the first shell and 8 on the second
• Protons have a charge of +1 and a mass of 1
• Neutrons have a neutral charge and a mass of 1
• Electrons have a charge of -1 and a very small mass
• Electrons are the same as protons
• The top number on an element is the mass number which is the number of protons and neutrons
• The bottom number of an element on an element is the atomic number which is the amount of just the protons
• Protons are the same number as electrons
• Every element has a physical and chemical property

  • A chemical property is how it reacts with other materials e.g reacting with air
• A physical property is how it behaves without changing chemically e.g boiling point
• A compound is more than one element that are chemically bonded together that have different properties
• When two or more different elements react with each other they lose their old properties and gain new ones
• An atom is neutral because the number of protons and electrons are the same
• a nucleas is neutral because it has protons and neutrons
• Rules to write an equation

  • The metal comes before the non metal
  • The second element ends in 'ide'
  • If the 3rd element is oxygen the 2nd element will end in 'ate'
• When elements react to make a compound the charges must cancel each other out
• Magnesium fluoride->magnesium fluoride

  MgF2
• A compound is when there is more than one type of atom that are chemically bonded together
• Properties vs Characteristics


  A property is an inherent trait of an element or compound, while a characteristic is determined by the surrounding conditions.
• A physical change is a change that can be observed by your senses
• A chemical change is when the atoms rearrange and a new bond is formed
• Total mass of reactants = total mass of product
• If a chemical reacts with oxygen or a gas it is easy for it to escape
• Magnesium Reacts with Oxygen


  Reaction: Magnesium (Mg) reacts with Oxygen (O2) to form Magnesium Oxide (MgO) + Heat. Observations: Changes in color, temperature increase.
• Group 1 of the periodic table is called the alkali metals and as you go down the reactivity increases and the density, and hardness also increases
• Group 7 is the halogens and as you go down the reactivity decreases and they are non metals
• Group 0 are the noble gasee and are unreactive the boiling point increases as you go down, they are colorless odorless and tastless
• Lithium, nitrogen, potassium rubidium, ceasium and francium are in group 1
• Fluorine, chlorine, bromine, iodine, stating and tennestine are in group 7 
• Helium, Neon, argon, krypton, xenon, radon and oggnesson are on group 0
• Flurine


  Yellow
• Chlorine


  Pale red
• Bromine


  Red brown
• Iodine


  Grey
• Helium is used for balloons because it has a low density