Periodic Trends

LevelPrice Red Sections & $15 Red Sections , 119, $14 Yellow Sections & $13 Yellow Sections , , $12 How does the price change as we move from outside the arena inside, down toward the rink? The price increases as you get closer to the rink How does the price change as we move around a level? Some sections cost less

Atomic Radius Does an atom have a fixed radius? How can we measure the radius then? Half the distance between nuclei of two atoms of the same element

Thinking it through… What happens to the energy level as we move down a group? The energy level increases How is the energy level related to the size of an atom? The higher the energy level, the bigger the size The lower the energy level, the smaller the size What happens to the size of an atom as we move down a group? The size of an atom increases

Shielding Do all electrons see the nucleus the same? No! Why? Electrons between the nucleus and an outer electron shield the outer electron from the nuclear charge The outer electron does not experience the full nuclear charge

Shielding

Atomic Radii Increases down a group Energy level increases Increase in size (electron cloud) Opposite charges? Shielding effect prevents contraction of electron cloud

And this relates to tickets how? How do the section and ticket prices relate to the size of atoms? As you move down a section, the ticket price increases As you move down a group, the size of the atom increases

What about across? What happens to the energy level as we move across a period? The energy level stays the same How does the size of the atoms change across a period? The size of the atoms decrease

Atomic Radii Decreases across a period Same energy level Same size electron cloud Why does it decrease then? Increasing nuclear charge Electrons get pulled in toward nucleus Electron cloud contracts

And this relates to tickets how? Why are some sections in the same level less money? Increasing amount of obstruction Why does the size of the atom decrease across a period? Increasing nuclear charge

Ionic Radius Cations Always smaller than parent atom

Cation Formation

Ionic Radius Anions Always bigger than parent atom

Anion Formation

Why the Trend? The more positive an ion is the smaller it is because Z eff increases The more negative an ion, the larger it is because Z eff decreases

Electronegativity The ability for an atom to attract electrons while in a compound Atoms are bonded together Scale Fluorine is the most electronegative element Trend is the same as ionization energy

Summary