Periodic Trends

As we examine the periodic table each elements have certain characteristics and looking at the periodic table as a whole, some trends are noticed.

Recall that Dmitri Mendeleev created a periodic table of the 63 known elements which he arranged by atomic mass.

First we must know some important vocab.

Density: of an object is its mass per unit volume. It increases as the atomic numbers increase.
Ionization energy: is the energy needed to remove electrons from an atom. It increases as you go across a period(left----> right) and decreases as you go down in families.

Melting and Boiling Points: This is the temperature at which an object liquefies and  becomes a gas respectively.
These properties increase as you go from bottom to top in a group.

Electronegativity: This is the tendency of an atom or functional group to attract electrons towards itself(form negative ions) In increases left------------->right

Atomic Radius: Is the measure of the size of an atom. It decreases left to right and increases going down.