The Periodic Table

These are the electron atomic orbitals of Nitrogen and Oxygen. The electrons on the outermost circles (orbitals) are the valence electrons. Nitrogen has 5 valence electrons and Oxygen has 6 valence electrons.

● A row of elements is called a period, there are 7 of them. ● Each period has the same number of atomic orbitals.

A column of elements is called a group or a family. There are 18 of them. Groups have similar properties and the same number of electrons in the outer atomic orbital (or valence electrons).

Groups have similar properties: 3: Lithium 2,1 Both react with water, and are silvery light, soft, white metals. Low melting and boiling points, good conductivity.

Metals vs. Nonmetals in the Table ● There are more metals on the table than nonmetals. ● The zigzag line divides the metals from the nonmetals.

● The elements on the periodic table are arranged by atomic number (number of protons), and element properties. ● The atomic number increases as you move from left to right across the table. Arrangement of the Periodic Table

Element Information in the Periodic Table Each element has an element square with information about that element inside.

The light green spaces are the transition metals they don't have the same electron configuration rules.

Mendeleev (and others) 1860's 6 People invented the Periodic Table independently: ● Alexandre-Emile Beguyer de Chancourtois (atomic weights) ● William Odling (many things were right thought periods were a length of 8) ● Gustavus Hinrichs (published too much but had hard to place elements in the right groups) ● John Newlands (no noble gases - compared the table to do- re-mi.... Chemical Society was not impressed) ● Julius Lothar Meyer - shared awards with Mendeleev but... ● Mendeleev - does not believe in the existence of atoms.....but has guts, says elements will be discovered to fill in the table.