Modern Periodic Table

The Periodic Law In the modern periodic table, elements are arranged by increasing atomic number (increasing number of protons)

Rows on the Periodic Table Each row in the table of elements is a period. Each period has a different energy level associated with it. 1st energy level 2nd energy level 3rd energy level

Columns on the Periodic Table Each column on the periodic table is called a group or family. Properties of elements repeat in a predictable way when atomic numbers are used to arrange elements into groups.

Periodic Law Elements in a group have similar electron configurations. Elements in a group have similar chemical properties. The pattern of repeating properties is called periodic law.

Classes of Elements Three different ways to classify elements: Phase of matter at room temperature Naturally occurring vs. not naturally occurring General properties Metals (on left side) Nonmetals (on right side) Metalloids (in middle)

Metals Elements that are good conductors. Solid at room temperature (except Mercury) Most are malleable. Many are ductile (drawn into wires) Transition metals (groups 3-12) Form a bridge between the left and right sides of table. Form compounds with distinctive colors. cool reactions more cool reactions

Nonmetals Elements that are poor conductors Elements have low boiling points Many are gases at room temperature Some are solids at room temperature but are very brittle.

Metalloids Properties of this group vary. For example, a metalloids ability to conduct electricity varies with temperature.

Variation Across a Period Across a period, from left to right, the elements become less metallic and more nonmetallic in their properties. Most reactive metals on left side Most reactive non-metals on the right side more cool reactions