The Periodic Table of Elements Dmitri Mendeleev 1834

The Periodic Table of Elements

Dmitri Mendeleev (1834 -1907) • Russian Chemist • Published the first version of the period table in 1869 • Arranged elements according to increasing atomic mass • His periodic table had gaps

Henry Moseley (1887 -1915) • Made improvements to Mendeleev’s Periodic Table • Arranged elements by atomic number instead of mass • Realized that there were undiscovered elements

The periodic table holds all the • chemical elements found on Earth.

Describe the Periodic Table • Elements are arranged left to right and top to bottom in order of increasing atomic number.

Introducing: The Atom • https: //www. youtube. com/watch? v=hhbq. IJZ 8 w. CM • Elements have different atomic numbers - the number of protons or electrons increases up the table as electrons fill the shells.

Describe the Periodic Table. The number of protons plus neutrons in the nucleus of the atom is the atomic mass. Each element has a different atomic mass. This number increases as you go across the rows from top to bottom of the table.

The different rows of elements are called periods. – All elements have something in common if they are in the same row. All of the elements in a period have the same number of atomic orbitals or electron shells. Every element in the top row (the first period) has one orbital or shell for its electrons. All of the elements in the second row (the second period) have two orbitals (shells) for their electrons. It goes down the periodic table like that. At this time, the maximum number of electron orbitals (shells) for any element is seven.

The different columns of elements are called groups or families Elements in the same family have similar properties, just like family members have similar characteristics.

Describe the Periodic Table

Describe How To Read The Periodic Table

Describe how to read the periodic table: • Every table has blocks that look similar to this: • There are 92 naturally occurring elements on the periodic table.

Describe how to read the periodic table: Atomic Number The number of protons in an atom identifies the element. The number of protons in an atom is referred to as the atomic number of that element.

Describe how to read the periodic table: Atomic Symbol: The atomic symbol is one or two letters chosen to represent an element ("H" for "hydrogen, " etc. ). These symbols are used every where in the world Usually, a symbol is the abbreviation of the element or the abbreviated Latin name of the element.

Describe how to read the periodic table: Atomic Mass: The atomic mass is the average mass of an element in atomic mass units ("amu"). The first 20 elements have an atomic mass about two times the atomic number.

https: //www. youtube. com/watch? v=0 pd. Rxrmg. Ro. Q Metals • Metals are commonly: 1. Shiny 2. Good conductors of heat and electricity 3. Have high melting point 4. Malleable (this means that they can be hammered or distorted) 5. Ductile (this means that they can be drawn into wires) 6. Usually solids at room temperature. An exception to this is mercury, which is liquid in nature. • Most elements on the Periodic Table are metals, and can be found on the left side of the Transitional elements

• On your Periodic table, color in the Transitional Metals “zig-zag” which is made of elements 5, 14, 32, 33, 51, 52, and 64 in RED. These are known as Metalloids. • Then, color in the Metals to the left of this zig-zag in YELLOW. Don’t forget the two rows below the main table. These are metals, too!

The Noble Gases • Group 18 Elements -Helium -Neon -Argon -Krypton -Xenon -Radon • Helium is used to fill balloons. • Neon signs contain noble gases. • Color the family # 18 in purple. These are the Noble Gases.

Non-Metals • • Non-metals are commonly: Not shiny poor conductors of heat and electricity May be solids, liquids, or gas at room temperature • Noductile and brittle • These are found to the right of the Transitional Elements “zig-zag. ”

• The elements between the zig-zag and the Noble Gases are the Non-Metals. Color these in green.

More Periodic Table Identification fun!!!! 1. 1. Find hydrogen and draw a circle around it in pencil. 2. Find oxygen, and draw a circle around it in pencil. 3. Find nitrogen, and draw a circle around it in pencil. 4. Find carbon, and draw a circle around it in pencil.

Periodic Table Fun Facts! • There are 92 elements on the periodic table that occur in nature. • The present table has room for 118 elements. • Scientists are working on creating a verifying element 120, which will change the appearance of the table.

Questions 1. What are the names of the three groups of elements you colored in today? 2. How many elements occur naturally in nature? 3. ______ are the rows of the Periodic Table. 4. ______ are the columns of the Periodic Table.