Periodic Table

How are the elements arranged in the periodic table

Elements are arranged in order of increasing proton (atomic) number

What are the 7 horizontal rows called

Periods

What are the 8 vertical columns called

Groups

What does elements in a group have in common

They tend to have the same oxidation number, valency, and similar chemical properties

What are the trends in the periodic table

• Atomic radius

• Ease of ionization

• Electronegativity

• Other physical properties

• Reactivity

Define atomic radius

Atomic radius is a measure of the size of an atom

Define ease of ionization

Ease of ionization is the ability of an atom to lose electrons to form positive ions

Define electronegativity

Electronegativity is the ability of an atom to attract a bonding pair of electrons to itself in a covalent bond

What are other physical properties

Melting point, boiling point and electrical conductivity

Define reactivity

Reactivity is how easily an atom loses or gains electrons to achieve a stable electronic configuration

Describe the atomic radius going down the group

Atomic radius increases down a group.

Down the group each element has one more electron shell than the previous element. The inner electron shells “shield” the outer shells from the full charge of the nucleus. The atomic radii therefore increase as shells move further away from the nucleus

Describe the ease of ionization going down the group

The ease of ionization increases down the group

since outer electrons are further from the nucleus and are therefore more weakly held. This also means that there is an INCREASE IN METALLIC CHARACTER down a group

Describe electronegativity going down the group

Electronegativity decreases down the group.

As the nucleus becomes more shielded by inner electron shells, the ability of the nucleus to attract electrons to itself decreases