TRENDS IN THE PERIODIC TABLE

Trends in the Periodic Table The arrangement of elements in the

periodic table into groups and periods with predictable properties allows us to assume certain patterns in the electron configurations.

Other properties of elements follow predictable patterns in the periodic table: Atomic Radius Ionization Energy Metallic Character Electronegativity

Atomic radius is ½ the distance between the nuclei of 2 like atoms

As you move DOWN a group, atomic radius INCREASES

As you move LEFT to RIGHT across a period radius DECREASES

Atomic Radii

Atomic Radius

As you move across the period you gain electrons but you also gain protons. More + protons hold their electrons tighter

As you move down the group you gain more electrons which are in electron orbitals further from the nucleus. The nucleus has less pull the further out you move.

Ionization Energy (IE)

Ionization Energy is the energy required to remove 1 electron from an atom. (Make a + ion) Low IE – Easy to remove the electron High IE – Hard to remove the electron

As you move DOWN a group ionization energy DECREASES

As you move LEFT to RIGHT across a period ionization energy INCREASES

Ionization Energy

Atoms on the left of the periodic table give up electrons easily to achieve a more stable electron configuration.

The valence electrons in atoms lower in the group experience less pull from the + protons in the nucleus and are easier to remove.

Lower IE

Low IE

High IE

The Noble Gases have the highest IE of all because they are in the most stable configuration.

Electronegativity Electronegativity is the tendency of

an atom to attract electrons in a compound. The higher the electronegativity, the more the

atom is able to attract electrons to itself.

As you move DOWN a group Electronegativity DECREASES

As you move LEFT TO RIGHT across a period Electronegativity INCREASES

Electronegativity

As you go down a group, electronegativity decreases because the bonding pair of electrons is increasingly distant from the attraction of the nucleus.

Electronegativity increases across a period because the number of charges on the nucleus increases. That attracts the bonding pair of electrons more strongly.

Metallic Character

Metallic character is the tendency of an element to be shiny, silver, malleable, ductile and to react to form positive ions

As you move DOWN a group metallic character INCREASES

As you move LEFT TO RIGHT across a period metallic character DECREASES

Metallic Character

Increasing Metallic Character

Overview of Trends