THE MATERIAL WORLD ATOMS

THE MATERIAL WORLD ATOMS

1. ATOMS

   • all matter is made of atoms
   • size: 0.0000000001m
   • In a neutral atom there is the same number of electrons and protons
   • Electrons move around the nucleus at very high speeds
   • Atomic parameters
     • Z:ATOMIC NUMBER number of protons in the nucleus
     • N: number of neutrons in the nucleus
     • A:MASS NUMBER:: number of protons+number of neutrons
     • ATOMIC MASS: is the average mass of its isotopes according to their relative abundance
   • ISOTOPE: atom with same atomic number, different number of neutrons
   • IONISATION: when atoms gain or lose electrons
     • atoms can be ionisaded by
       • FRICTION
       • ELECTRICAL DISCHARGES
       • COLISION BEETWEEN PARTICLES
       • HIGH TENPERATURES
     • CATIONS :lose electrons and have a positive charge
     • ANIONS: atoms that gain electrons and have a negative charge

2. Electrical Phenomena

   • when we rub certain materials it causes electric phenomena
   • Electrical Phenomena exhinit eitheir atracción or repulsion
   • Electric charge
     • causes electric phenomena atracción and repulsión wich we observe in nature
       • Electric charge of the same type repels each other
       • Opposite electric charges atracct each other
     • Positive charge
     • negative charge

3. Particles of an atom

   • ELECTRONS
     • John Thomson find out with his experiments a very small particle called elctron
     • Characteristics
       • are part of atoms
       • they are 1840 times smaller than atoms
       • they have a negative charge
   • PROTONS
     • Split them out of the nucleus by nuclear fission
     • Characteristics
       • are at nucleus of all atoms
       • similar mass than a hydrogen atom
       • Have a POSITIVE charge
   • NEUTRONS
     • James Chadwick proved Rutherford's theory of neutrons in1932
     • Characteristics
       • Toghether with protons form the nucleus of an atom
       • Same mass as protons
       • Have no electric charge they are neutral

4. The organisation of atoms in matter

   • Characteristics
     • A chemical element represents all atoms of the same type
     • the atomic number Z defines the type of chemical element and separates it from all other
     • chemical elements are organised in the periodic table
   • TYPES of substances
     • SIMPLE
       • is made up from atoms of THE SAME chemical element
         • 3 TYPES of organisement
           • SINGLE
           • LARGE CLUSTERS
           • MOLECULES
     • COMPOUND
       • is made up from atoms from DIFFERENTS chemical elements
         • organisement of atoms
           • molecules
           • clusters of ions with different charges

5. chemical formula

   • It is a symbolic representation of the elements that group up to form substances
     • simple ATOMS
     • compound ATOMS

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