Periodic Law

							The Periodic Law Periodic Table of Elements video

Development of the Periodic Table  Dmitri Mendeleev developed the first periodic table  The periodic table is an arrangement of elements according to their chemical and physical properties

Mendeleev’s Periodic Table
 Mendeleev arranged the elements

according to their atomic masses  The elements followed a pattern of 1 2 3 4 3 2 1 (valence electrons)  video

Questions
developed the first periodic table?  What is the periodic table?  What are valence electrons?  How did Mendeleev arrange elements in the first periodic table?
 Who

Periodic
 Refers

to repeating according to a pattern

Questions
 Why are the days of the week

and the months of the year periodic?

Modern Periodic Table video  Henry Moseley determined the atomic number of the elements  Elements in the modern periodic table are arranged according to atomic numbers  video

Periodic Law
 States that the physical and chemical

properties of elements are periodic functions of their atomic numbers  Properties of elements have some pattern according to their atomic numbers

Questions
 What is the major difference

between Mendeleev’s periodic table and the modern periodic table?

Columns in the periodic table
 Columns of elements are

known as groups or families  Elements in a family have similar properties

Rows in the periodic table
 The horizontal rows of

elements are called periods  The elements in a period do NOT have similar properties

Periods
 First element in a period is an

active solid  Last element in a period is an inactive gas

Questions
 What is the major difference

between periods and families?  How are elements in a family similar?  How are elements in a period different?

Element squares in the periodic table
 The basic information found in each

square of the periodic table :  Atomic number  Chemical symbol  Element name  Atomic mass  video

Elements
 Elements are classified as:
 Metals  Nonmetals  Metalloids

Questions information is found in the squares on the periodic table?  How can an element be classified?
 What

Characteristics of Metals (video)
 Good conductors of heat and

electricity  Shiny; High melting points  Malleable (bends easily)  Ductile (can be made into wires)  Found on the LEFT of the periodic table

Questions is the difference between ductile and malleable?  Where are metals found on the periodic table?
 What

Properties of Nonmetals
 Dull

(hard/ easily broken)  Found on the RIGHT of the periodic table  video

 Brittle

Properties of Metalloids
properties of both metals and nonmetals  Found touching the dark, zigzag line  Metalloid means “metal-like”  video
 Has

Questions is a metalloid?  Where are metalloids located in the periodic table?  Where are nonmetals located on the periodic table?
 What

Periodic Properties of Elements (Modern Table)
pattern across a period is 1 2 3 4 3 2 1 0 (left to right)  Metals lose electrons easily  Nonmetals gain electrons easily
 Valence

Periodic Properties of Elements
size of the atom decreases from left to right across a period  The metallic properties of elements decrease from left to right across a period  Elements on the left are more reactive than the elements on the right
 The

Questions
happens to metallic properties as one moves from left to right across a period?  What is the valence pattern of electrons across a period?  video
 What