The Periodic Table Periodic Properties of Elements Periodic Law The Periodic Table Periodic Properties of Elements

Development of the Periodic Table-Mendeleev Dmitri Mendeleev Studied elements Grouped elements with similar properties together Arranged elements in order of increasing atomic mass

Mendeleev

Development of the Periodic Table-Modern Modern Periodic Table Henry Mosely determined atomic numbers of the elements Elements are now arranged in order of increasing atomic number.

Atomic number Atomic mass

Development of the Periodic Table-Terms Columns of the periodic table are called groups or families Rows of the periodic table are called periods Periodic law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

Modern Periodic Table

Periodic Properties: Metals, Nonmetals and Metalloids Metals give up electrons easily. They are found on the left side of the periodic table Nonmetals have a tendency to gain electrons. They are on the right side. Metalloids are found on the zigzag line between metals and nonmetals.

Metals Nonmetals

Properties of Metals Shiny Ductile Malleable Give up electrons easily Good conductors of heat and electricity sodium copper mercury

Properties of nonmetals Dull Brittle Nonconductors Usually gases or liquids at room temperature bromine sulfur

Periodicity Elements vary in a regular way across the table. Examples: Valence number Reactivity Ionization energy Atomic size Melting and boiling points

Periodicity: Valence numbers Valence electrons are shown in red (note: transition elements not shown in this table)

Periodicity: chemical reactivity of elements most reactive least reactive most reactive

Periodicity: atomic radii