Periodicity and properties of elements

• Proton number = bottom number = number of electrons
• Neutrons = mass number - number of protons/electrons
• A non-polar bond is when electrons are distributed evenly.

  A polar bond is when the electrons are not distributed equally.

  ->The element with the higher electronegativity attracts shared electrons more strongly making it partially negative.
• Group of element= number of electrons on outermost shell.

  Period= amount of shells it has.
• An element is classified as "s-block" because the orbital on its outermost shell is S.
• Aufbau principle states that electrons fill the orbital with the lowest available energy state.