Periodic Table

• This table is a remarkable way to show the manifold relationships between differing kinds of elements

• The modern table was devised in 1869 by Dimitri Mendeleyev

• He arranged the elements by weight and by their chemical properties

Periodic Table

• "...if all the elements be arranged in order of their atomic weights a periodic repetition of properties is obtained." - Mendeleyev

Some element facts…

Periods and Groups

• Horizontal rows in the periodic table are called periods

• Vertical columns are called groups

• We will learn later why the elements can be arranged in this fashion based on the arrangements of the electrons outside the nucleus

Groups vs periods

Periods and Groups

• Sizes of the atoms decrease as we move from left to right across a period

• This is due to the increasing number of protons in the nucleus, so the electrical attraction between the nucleus and the orbiting electrons gets stronger and pulls the electrons closer to the nucleus

Relative Radii

Periods and Groups

• We can display the table to demonstrate other properties as well

• As you move from left to right across a period, the ability of the atom to attract another electron increases

• This property is called electronegativity

Ease of losing an electron

Periods and Groups

• All the elements in a column have remarkably similar chemical properties

• Some of the columns have been given special names to distinguish them

• The first group is called the alkali metals

• The second group is the alkaline-earth metals

Periods and Groups

• Groups 3-12 are called the transition metals

• Groups 13-15 are not named

• Group 16 are the chalcogens

• Group 17 are the halogens

• Group 18 are the noble gases and are basically inert

Modern Periodic table

Questions to hand in

1. Which elements are in the in the first period?2. Elements in the second and third periods are

having which sublevels filled?3. Which element has the first “d” electron?4. Which element has the first “f” electron?5. Place the following elements in order from

smallest to largest radius: Ba, Ca, Mg, Sr, Be6. Place the following elements in order from

smallest to largest ionization energy:Ba, Ca, Mg, Sr, Be

7. Place the following elements in order from smallest to largest radius: K, Mn, N, Rb, Cl, Ne

Questions continued

8. Place the following elements in order from lowest electronegativity to highest electronegativity: Y, F, O, Cs, Fe, I

9. Transition metals typically have full ______ sublevels, partially filled ______ sublevels, and empty ______ sublevels.

10. The Lanthanide and Actinide series contain the only elements that have partially filled _______ sublevels.