PERIODIC TABLE OF THE ELEMENTS

 

 

Unit Introduction

In the last two units, you have been exposed to some information about the periodic table. The purpose of this unit is to give you an overview of the history, allow you to more thoroughly understand the information on the periodic squares, and to investigate trends on the periodic table.

History of the Periodic Table

The periodic table organizes all known elements in the universe. Dmitri Mendeleev is thought to be the father of the modern periodic table, but several other scientists have helped in the development of its current format. The elements are arranged chronologically according to atomic number in the modern periodic table. Not all currently known elements were on Mendeleev’s periodic table. He was able to classify and arrange the elements known at the time as well as predict the spots that future elements would fit into. This is what set Mendeleev’s periodic table apart from others that were being developed.

 

The First Periodic Table:

 

What you see below is Mendeleev’s organization of elements according to their increasing atomic weights. You can see the blank spaces at the bottom where he knew other elements would be discovered and fit into those places.

 

 

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Please read the following article, which has more information about Mendeleev’s personal and professional life. As you read, construct a timeline of his life. Submit your work as question #15 in the assessment portion of the unit.


 

 

Printable: Timeline Document

 

Squares of the Periodic Table

There are over 100 known elements at this time. Each element has its own square on the periodic table. Each square displays the same information, though one periodic table can have the information arranged differently from another periodic table. Here is a close-up view of what is on the periodic square for carbon—

 

 

Carbon is number 6 on the Periodic Table

 

 

If you need to know an element’s symbol, atomic number, or atomic mass, you can look to the periodic table to find this information and more.

Practice: Fill in the blanks for the element vanadium using the periodic square. Record your answers for questions 1-3 in the assessment portion of the unit.

 

 

Image result for vanadium periodic square

1. Element symbol: ____________________

2. Atomic mass: ______________________

3. Atomic number: _____________________

 

 

Periodic Table Organization

The periodic table is organized according to increasing atomic numbers of the elements. Hydrogen, the first element, has the atomic number of 1. Helium, the next element, has the atomic number of 2. When elements are listed in order of increasing atomic number, the same sequence of properties appears over and over again; this is the periodic law. The periodic table can be read similar to reading text—left to right and top to bottom.

One may wonder why the periodic table has such an unusual shape.  By arranging elements in the configuration that is shown, they are close to elements with similar properties.

A group is a vertical column in the periodic table. Elements in the same group have very similar properties to one another. Elements in the same group also have the same number of valence electrons, which helps to predict how they will form compounds with other elements.

 

 

Image result for periodic table groups periods

 

 

A period is a horizontal row of the periodic table. Elements in the same period have the same number of orbitals, or shells, for electrons.

 

 

Image result for periodic table groups periods

 

 

Metals, metalloids, and nonmetals can be easily found in large groupings across the periodic table. Looking at the periodic table below, you will notice that the metals are all found on the left side.  Most of the elements are metals.  Hydrogen (H) is a gas but it is placed on the left side above the Alkali Metals.  Hydrogen is a family of one.  The nonmetals are found on the right side of the periodic table.  If you look closely at the periodic table you will notice a dark, stair-step line.  This line divides the metals from the nonmetals.  The elements found along this line are known as the metalloids.  They have properties of both metals and nonmetals.  Aluminum (Al) is found along this line, but it is a true metal not a metalloid.

 

 

Image result for periodic table groups periods

 

 

Element Groups

The element groups on the periodic table are referred to by their group numbers or names. The group numbers are listed 1-18 across the top of the periodic table, or if the transition metals are skipped over, the rest of the groups are listed as 1A-8A across the top of the periodic table. You can see both numbering schemes on the periodic table below.

 

 

Image result for element groups

 

 

Group 1 is known as the alkali metals. All elements in group 1 except for hydrogen are included. They are soft and gray in color. They are extremely reactive, and you rarely see them as elements in nature because of their strong tendency to form compounds with other elements. All elements in group 1 have 1 valence electron.

 

 

 

 

Group 2 is known as the alkaline earth metals. They are also reactive but not as reactive as the Group 1 elements. All elements in group 2 have 2 valence electrons.

 

 

 

 

Group 17 is known as the halogens. Halogens are very reactive nonmetals and have a strong tendency to form compounds with Group 1 elements. All elements in group 17 have 7 valence electrons.

 

 

 

 

The noble gases are found in Group 18. They have a full outer shell of electrons, which means they are stable and exist as elements in nature.

 

 

 

 

Watch the following video for more information about the organization of the periodic table:

 

 

 

 

Element Uses

Each element on the periodic table is unique. Consequently, the elements are useful in many different ways. Check out the link below to learn more about common uses of each element. Select 20 elements and describe their uses. Find a picture to include for each chosen element.

http://elements.wlonk.com/ElementUses.htm

 

Element Puzzle

Element Puzzle Clues