Periodic Trends

Organization… When Mendeleev organized his table, he saw that ___________ showed up at regular intervals, called ________. properties periods Some of these properties show definite _______… trends

Atomic Radius We usually think of atoms as ________, but they are a lot more complicated! spheres The number of ________ determines the number of ______________ outside the nucleus, and therefore the _____ of the atom. electrons energy levels size The size of an atom is the atomic _______. radius

The bigger they are… The more energy levels, the ______ the atom, and the _______ the atomic radius. bigger larger So as you move down a group, atomic radius will _________. increase

The bigger they are… But what happens when you move ______ a period? across The atomic ______ increases, which means the number of ______ increase. number protons **Remember that protons have a _______ charge and electrons have a ________ charge, so they will be __________ to each other… positive negative attracted

Attractive forces The more protons there are, the ________ the attraction for the ________. stronger electrons This pulls the electrons _______ to the nucleus, and _________ the atomic radius. closer decreases As you go across a period, atomic radius will ________. decrease

Atomic Radius

Ionization Energy Ionization energy is the _______ of energy needed to ________ one of the __________ in the _________ shell. amount remove electronsvalence The ________ the electrons are to the nucleus, the ________ the ionization energy. closer greater

Why? Remember that the nucleus has a _________ charge and electrons have a _________ charge… positive negative The closer the electrons are to the nucleus, the _________ the attractive forces, and the ________ to pull them apart. stronger harder

Energy Trends As you travel across a period, the nuclear charge _________, so the electrons are held more _______. increases tightly Ionization energy _________ as you travel from left to right across the same _______. increases period

Energy Trends As you go down a column, you add an ____________ with each period. energy level This increases the _________ between the ________ shell and the ________, so the attractive forces will _________. distance valence nucleus decrease So ionization energy __________ as you go down a column. decreases

Ionization Energy

Electronegativity Electronegativity is the tendency to attract _________ to fill your ________ shell. electronsvalence The more _____ your valence shell, the ________ your ability to attract electrons. full greater So as you move across a period, electronegativity will Increase____.

Electronegativity As you move across a period, the _______ shell gets _______. valencefilled A full valence shell is more _______ than an unfilled one. stable The closer you get to a full valence shell, the ________ your electronegativity. greater So electronegativity __________ as you move across a period. increases

Electronegativity As you move down a column, the valence shell gets ________ from the nucleus. farther This _________ the attractive forces between the _________ and the _________. decreases nucleus electrons Electronegativity _________ as you move down a column. decreases

Electronegativity