atoms, elements and compounds

atoms, elements and compounds

1. elements

   • elements are in the periodic table
   • elements are made out of one kind of atom
   • most are put into groups
     • these groups are called group 1, 2, 3, 4, 5, 6, 7 & 0
     • elements in the same group have similar physical and chemical properties
     • elements in the same group all have the same number of electrons in the outer shell

2. atoms

   • these atoms are what makes up elements
     • the atoms are different for each element
   • atomic struture
     • nucleus
       • the nucleus holds the protons and the neutrons
         • protons
           • they have a positive charge and a mass of 1
         • neutrons
           • they have no charge and a mass of 1
         • protons and neutrons added together create the mass number
     • shells
       • the shells of an atom are what holds the electrons
         • the first shell holds 2 electrons every other shell holds eight
           • to show the nuber of electrons and how many shell it has. it can be wrote like this
             • 2.8.8.7
               • this element would be in group 7 because it has 7 electrons in the outer most shell
         • electrons have a negative charge and no mass
     • atoms are neutral (have no charge) because the protons and electrons cancel each other out

3. compounds

   • compounds are created when 2 or more elements are bonded together
   • the atoms in a compound are called ion atoms
     • this is where two or more atoms are bonded