Atomic Structure & Periodic Table

Atomic Structure & Periodic Table

1. ATOMS

   • nucleus= p & n, +ve charge, whole mass
   • electrons= surround nucleus, in shells, -ve charge, no mass
   • protons= electrons= neutral
   • ATOMIC & MASS NUMBERS
     • atomic number= number of protons
     • mass number= number of protons & neutrons
     • number of neutrons= mass number - atomic number

2. IONS

   • atom or group of atoms that have lost or gained electrons
   • protons not = to electrons = +ve or -ve charge

3. ELEMENTS

   • elements consist of atoms with the same atomic number

4. ISOTOPES

   • same as element just extra neutrons
   • same number of protons, different number of neutrons
   • relative atomic mass is an average taking into account the different masses and amounts of all the isotopes that make up the element

5. COMPOUNDS

   • atoms join together to make compounds
   • substance with 2 or more elements in fixed proportions chemically bonded together
     • IONS - metal & non-metal compound
       • a compound which is formed from a metal and a non-metal consists of ions
       • metal atoms lose electrons= +ve ions
         • non-metal atoms gain electrons= -ve ions
         • ionic bonding - give away / gain electrons
     • MOLECULES - Non-metal compounds
       • a compound formed from non-metals consists of molecules
         • each atom shares an electron with another atom
         • covalent bonding - share electrons
   • MAKING BONDS
     • atoms giving away, taking or sharing electrons

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