Atoms and the Atomic Model

• Elements in Group 18 of the periodic table. Have no charge and are gases under normal conditions. (Helium, Neon, Argon, Krypton, Xenon, Radon)


  Noble gases

  
• Contains nonmetals, 7 valence electrons in it's outermost energy level. Very reactive

  Halogens

  
• The basic building block of all materials; it consists of neutrons and protons surrounded by a cloud of electrons

  Atom

  
• The fundamental building block of all materials; it consists of a bunch of neutrons and protons surrounded by a cloud of electrons

  Atomic model

  
• The number of protons in a neucleus; the atomic number determines what type of atom it is

  Atomic number

  
• A short-hand notation for describing an atom; it consists of the chemical "letter(s)", atomic number and mass number

  Atomic symbol

  
• A small, negatively charged particle; clouds of electrons surround the nucleus of an atom

  Electron

  
• The number of electrons in each of the electron shells of an atom

  Electron configuration

  
• Part of the electron cloud; it is a layer that surrounds the nucleus and can only hold a certain number of electrons

  Electron shell

  
• An atom that has gained or lost electrons and therefore has an electric charge

  Ion

  
• Atoms that have the same number of protons (atomic number) but a different number of neutrons in their nucleus


  Isotope

  
• The number of protons and neutrons in an atom's neucleus

  Mass number

  
• Nucleus


  The centre of an atom, containing protons & neutrons
• Periodic table


  A table showing the symbols and often data of all 118 known types of atoms (elements)

  
• Proton


  A positively charged particle in the nucleus

  
• + Charge on a proton
• - Charge on an electron
• No charge


  Charge of a neutron
• Proton and Electron


  Equal but opposite charges
• Proton and Neutron


  Both live in the nucleus
• 1 atomic mass unit


  The weight of protons or neutrons.
• 1/1800th of an atomic mass unit.


  The weight of electrons.
• Mass number


  protons + neutrons
• In a normal atom:

  Number of electrons =


  Number of protons
• In an ion:

  Number of electrons =


  Changes (more or less) to get a full outer shell
• Atomic substance


  Atoms that are not bonded to other atoms. e.g. noble gases
• Molecular substance


  Contains molecules, each molecules has two or more atoms bonded together.
• Isotopes will have the same number of

  Protons
• Isotopes will have different numbers of

  Neutrons
• Noble gases


  Elements in Group 18 of the periodic table. Have no charge and are gases under normal conditions. (Helium, Neon, Argon, Krypton, Xenon, Radon)

  
• Atom


  The basic building block of all materials; it consists of neutrons and protons surrounded by a cloud of electrons

  
• Atomic model


  The fundamental building block of all materials; it consists of a bunch of neutrons and protons surrounded by a cloud of electrons

  
• Atomic number


  The number of protons in a neucleus; the atomic number determines what type of atom it is

  
• Atomic symbol


  A short-hand notation for describing an atom; it consists of the chemical "letter(s)", atomic number and mass number

  
• Electron


  A small, negatively charged particle; clouds of electrons surround the nucleus of an atom

  
• Electron configuration


  The number of electrons in each of the electron shells of an atom

  
• Electron shell


  Part of the electron cloud; it is a layer that surrounds the nucleus and can only hold a certain number of electrons

  
• Ion


  An atom that has gained or lost electrons and therefore has an electric charge

  
• Isotope


  Atoms that have the same number of protons (atomic number) but a different number of neutrons in their nucleus

  
• The number of protons and neutrons in an atom's nucleus

  Mass number