Periodic Trends Notes Chemistry Mrs. Stoops

Periodic Trends Really only considering the “s” and “p” section on the periodic table. Trends are all “opposites on the diagonal”

Periodic Trends Atomic Size – estimated size of an atom Not exact since exact location of outer most electron is not known Decreases Across – nuclear charge Increases Down – add more energy levels

Periodic Trends Electronegativity – Ability to attract e- Increases Across – the negative ions are on this side – they attracted electrons Decreases Down – farther from nucleus, harder to be attracted and held. Fluorine is the highest electronegativity on the periodic table.

Periodic Trends Ionization Potential (Energy) – Energy needed to remove an electron Increases Across – the energy needed gets higher – it is harder to remove an electron on the negative side of the table (gain electrons) Decreases Down – the energy needed gets lower – it is easier to remove an electron on the positive side of the table (lose electrons)

Periodic Trends Ionic Radius – estimated size of an ion (an atom that has lost or gained electrons). Not a smooth trend In the cation section (positive charges) electrons are lost, so the ionic radius Decreases Across In the anion section (negative charges) electrons are gained, the ionic radius Increases Across Increases Down – since elements in each additional row, adds an energy level, the atom and therefore the ion gains size.

Periodic Trends How would this be used? Which is bigger? Al or Al +3 OorO -2 Which is more likely to gain electrons (has a higher electronegativity)? Oor N MgorBa