Elements and the Periodic Table Chapter 17

Organizing the Elements MENDELEEV’S ORDER Dmitri Mendeleev Trying to organize the 63 known elements so they were easier to understand

Organizing the Elements MENDELEEV’S ORDER: Didn’t yet know about protons, neutrons and electrons, ONLY MASS.. What could he do?

Organizing the Elements MENDELEEV’S ORDER: Increasing Atomic Mass Elements with similar properties were put in the same column

Organizing the Elements Named “Periodic Table” because properties repeated ‘periodically’ from row to row. Like keys on a keyboard (octaves)

The Modern Periodic Table The Periodic Law Once protons were discovered, what were elements organized by?

The Modern Periodic Table Increasing Atomic Number.

The Modern Periodic Table Properties were STILL grouped by column.

The Modern Periodic Table So, Properties STILL repeated periodically (within a row).

The Modern Periodic Table Like Cards in a deck:

The Modern Periodic Table In the Modern table a PERIOD = a ROW. How many PERIODS are there? 7

The Modern Periodic Table PERIODS = ROWS How many ELEMENTS are in PERIODS 1, 2, & 3? What does this remind you of?

The Modern Periodic Table Numbers of electrons in each ENERGY LEVEL

The Modern Periodic Table In the Modern Periodic table a COLUMN = a GROUP ELEMENTS within a GROUP have similar PROPERTIES.

The Modern Periodic Table COLUMNS = GROUPS Therefore, properties repeat PREDICTABLY and PERIODICALLY.

The Modern Periodic Table THIS IS CALLED PERIODIC LAW.

The Modern Periodic Table There are 4 important pieces of information for each element Atomic number Element symbol Element name Atomic mass

The Modern Periodic Table CLASSES OF ELEMENTS: State: solid, liquid, gas Natural & manmade: (91 of the first 92 are natural) METALS, NONMETALS & METALLOIDS

The Modern Periodic Table Properties???? What happens to properties when you move from left to right across the table?

Representative Groups “A” GROUPS

GROUPS Elements in groups have SIMILAR (not identical) PROPERTIES because they have the SAME NUMBER OF VALENCE ELECTRONS

Be sure to use a different color for each of the items below. Journal Color in the Blank Periodic Table according to the following KEY. Be sure to use a different color for each of the items below. METALS NONMETALS METALLOIDS