Presentation on theme: "The Periodic Law Periodic Table of Elements video."— Presentation transcript:
The Periodic Law Periodic Table of Elements video
Development of the Periodic Table l Dmitri Mendeleev developed the first periodic table l The periodic table is an arrangement of elements according to their chemical and physical properties
Mendeleevs Periodic Table l Mendeleev arranged the elements according to their atomic masses l The elements followed a pattern of (valence electrons) l video video
Questions l Who developed the first periodic table? l What is the periodic table? l What are valence electrons? l How did Mendeleev arrange elements in the first periodic table?
Periodic l Refers to repeating according to a pattern
Questions l Why are the days of the week and the months of the year periodic?
Modern Periodic Table video video l Henry Moseley determined the atomic number of the elements l Elements in the modern periodic table are arranged according to atomic numbers l video video
Periodic Law l States that the physical and chemical properties of elements are periodic functions of their atomic numbers l Properties of elements have some pattern according to their atomic numbers
Questions l What is the major difference between Mendeleevs periodic table and the modern periodic table?
Columns in the periodic table l Columns of elements are known as groups or families l Elements in a family have similar properties
Rows in the periodic table l The horizontal rows of elements are called periods l The elements in a period do NOT have similar properties
Periods l First element in a period is an active solid l Last element in a period is an inactive gas
Questions l What is the major difference between periods and families? l How are elements in a family similar? l How are elements in a period different?
Element squares in the periodic table l The basic information found in each square of the periodic table : l Atomic number l Chemical symbol l Element name l Atomic mass l video video
Elements l Elements are classified as: l Metals l Nonmetals l Metalloids
Questions l What information is found in the squares on the periodic table? l How can an element be classified?
Characteristics of Metals (video)video l Good conductors of heat and electricity l Shiny; High melting points l Malleable (bends easily) l Ductile (can be made into wires) l Found on the LEFT of the periodic table
Questions l What is the difference between ductile and malleable? l Where are metals found on the periodic table?
Properties of Nonmetals l Dull l Brittle (hard/ easily broken) l Found on the RIGHT of the periodic table l video video
Properties of Metalloids l Has properties of both metals and nonmetals l Found touching the dark, zig- zag line l Metalloid means metal-like l video video
Questions l What is a metalloid? l Where are metalloids located in the periodic table? l Where are nonmetals located on the periodic table?
Periodic Properties of Elements (Modern Table) l Valence pattern across a period is (left to right) l Metals lose electrons easily l Nonmetals gain electrons easily
Periodic Properties of Elements l The size of the atom decreases from left to right across a period l The metallic properties of elements decrease from left to right across a period l Elements on the left are more reactive than the elements on the right
Questions l What happens to metallic properties as one moves from left to right across a period? l What is the valence pattern of electrons across a period? l video video