Electron Structure

• How many electrons can the first, second and third shell hold?

  2,8,8
• Carbon's atomic number is 6. What is it's electronic structure?

  2,4
• Magnesium's atomic number is 12. What is it's electronic structure?

  2,8,2
• The group number (columns ⬇) indicate how many electrons are in the outer shell.

  Eg. Sodium (Na) is in group 1 and therefore it has 1 electron on its outer shell.
• The period number (rows ➡) is how many electron shells the element's electronic structure has.

  Eg. Sodium (Na) has an electronic structure of 2.4, which (if drawn) has 2 shells. Therefore it is in period 2.
• Atoms bond to get full outer shells of electrons.

  Covalent bonding includes non-metal atoms sharing electrons to form molecules e.g. CO2

  Ionic bonding includes metals and non-metals, transferring electrons and forming charged ions. E.g. NaCl