The table we made as a class during the exploration:This table represents the largest number of trends using the given elements.

Dmitri Ivanovich Mendeleev and The Periodic TableThe Past, Present, and Future

Review

0 Atomic Number (Z): The number of protons in the nucleus of an atom. Represented by whole numbers.

Atomic Mass: The average mass of an atom of an element. 1

H1.007

0 Reactivity: A property that describes whether an element or compound will chemically combine with other substances to form compounds and also describes the speed of a reaction.

Introduction

0Who is Mendeleev, and what did he do?

0Mendeleev’s Table of Elements and its Trends

0The Modern Periodic Table and its Trends

0The Similarities and Differences Between these Two Tables

Dmitri Mendeleev(1834-1907)

0 Born in Verhnie Aremzyani village, near Tobolsk in Serbia.

0 He was a Russian Chemist

0 He is considered the father of the modern periodic table.

0 What did he know at the time?0 Atomic Mass of Elements0 Reactivity/ Properties of Elements

http://en.wikipedia.org/wiki/Dmitri_Mendeleev

Mendeleev’s Table of Elements

0 At the time of Mendeleev, only 63 elements were known.0 The Atomic Weights of Each (Some turned out to be wrong)0 The Properties of Each

0 Used this knowledge to create a table of elements

0 On Feb 17, 1869, Mendeleev Published “An Attempt at a System of Elements, Based on Their Atomic Weight”0 This is his first draft. Many revisions followed.

http://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/Mendeleev%27s_1869_periodic_table.png/300px-Mendeleev%27s_1869_periodic_table.png

The Trends And Missing Links

0Trends that can be seen on Mendeleev’s table (Look at Handout: Mendeleev’s Table Flipped 90 degrees) :0 Increasing Atomic Weight0 Properties of the Elements

0What is missing?0 Elements with Question Marks

0Not sure about the placement0 Atomic Weights with Question Marks

0Predicted Elements that had this atomic weight

The Modern Periodic Table of

Elements

https://encrypted-tbn1.google.com/images?q=tbn:ANd9GcRbLABkAGOTKN7b1pEg2doiOjwfPTDECVZziHFLcGdvk0XNsbJtoA

The Trends0 Increasing Atomic Number (Periodic Law)

0 When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

0 Increasing Atomic Weight0 Properties (Metals, Metalloids, and Nonmetals)0 Reactivity0 There are columns called groups that are represented by a number

that increases from left to right on table.0 There are rows call periods that increase top to bottom on the table.0 Could there be missing elements that we have not yet discovered?

http://www.dreamstime.com/stock-photography-stock-photography-question-mark-thinker-image9271642

Compare and Contrast

0 How does Mendeleev’s table of elements compare to the modern table of elements? (Look at Handouts)0 Similarities:

0 Increasing Atomic Weight in Both (For the Majority of the table: Some exceptions (Example: Te(127.6) and I(126.9))

0The column in Mendeleev’s table are similar to the rows in the modern table.

0 Differences:0There are more elements known today that are on the modern table.0 Some of the element names and atomic weights have changed a little

(More accurate measurements can be made now.)0The arrangement of the columns and rows are different