Periodic Table of Elements

Elements Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth. Scientists have identified 90 naturally occurring elements, and created about 28 others.

Elements The elements, alone or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe.

The “Father” of the Periodic Table  Dimitri Mendeleev was the first person to publish an organization of the elements.  Mendeleev organized the known elements in order of their atomic mass.  He correctly predicted the existence of unknown elements (Si, Al, Ga) Dimitri Mendeleev

Periodic Table The modern periodic table organizes the elements according to their atomic number. Physical and chemical properties of an element can be predicted simply by its position in the periodic table.

Symbols All elements have their own unique symbol. It can consist of a single capital letter, or a capital letter and one or two lower case letters. C Carbon Cu Copper

Common Elements and Symbols What are the symbols for the following elements? 1. sodium 2. silver 3. beryllium 4. iron 5. lead 6. hydrogen 7. oxygen 8. gold 9. copper 10. phosphorus

Common Elements and Symbols What are the symbols for the following elements? 1. sodium Na 2. silver Ag 3. beryllium Be 4. iron Fe 5. lead Pb 6. hydrogen H 7. oxygen O 8. gold Au 9. copper Cu 10. phosphorus P

Common Elements and Symbols What are the names of the elements with the following symbols? 1. K 2. N 3. Li 4. Ne 5. Ca 6. C 7. Ar 8. Sn 9. Zn 10. Cl

Common Elements and Symbols What are the names of the elements with the following symbols? 1. Kpotassium 2. N nitrogen 3. Li lithium 4. Ne neon 5. Ca calcium 6. C carbon 7. Ar argon 8. Sn tin 9. Zn zinc 10. Cl chlorine

Atomic Number The atomic number refers to how many protons an atom of that element has. No two elements have the same atomic number.

Atomic Mass The atomic mass refers to the mass of an atom. It is calculated by adding the number of protons to the number of neutrons. The unit of measurement for the mass of an atom is AMU – atomic mass unit One AMU is equal to the mass of one proton. It is also equal to the mass of one neutron.

Isotopes Usually, most atoms of an element have the same number of neutrons, but some don’t Some atoms of the same element have fewer or more neutrons than what you would calculate using the periodic table Each atom of an element with a different number of neutrons is called an isotope

Isotopes All of the atoms of an element that exist are one of its isotopes All of the isotopes for a single element have the same number of protons The three Isotopes of Hydrogen

Isotopes The atomic mass on the periodic table is the number of protons plus the average number of neutrons found in all of the isotopes for that element That is why the atomic mass on the periodic table has a decimal place

Valence Electrons These are the electrons in the outer most orbit or shell of an atom Valence electrons are important in determining the chemical properties of an element

Structure of the Periodic Table There are three types of elements on the periodic table: metals, non-metals and metalloids Metals are found on the left side of the zig- zag line.  Non-metals are found on the right side of the zig-zag line Metalloids are found on the zig-zag line

Metals, Metalloids, & Non-metals

Which of the following are metals? a) sodiumb) nitrogen c) bromined) calcium e) xenonf) zinc a) sodium d) calcium f) zinc

Properties of Metals Metals are good conductors Metals are shiny Metals are ductile Metals are malleable Metals react with water resulting in corrosion All but one are solids at room temp.

Properties of Non-metals Non-metals are poor conductors Non-metals are not ductile or malleable Solid non-metals are brittle They are dull They can be solids, liquids, or gases at room temp.

Properties of Metalloids Metalloids have properties of both metals and non-metals They are solids that can be shiny or dull They conduct heat and electricity better than non-metals, but not as well as metals They are ductile and malleable

Structure of the Periodic Table Vertical columns are called Groups or Families

Families or groups on the Periodic Table Elements that are in the same family or group have similar physical and chemical properties. It was these properties that Mendeleev used to create the table.

Families All of the elements in a family have the same number of valence electrons

Hydrogen Hydrogen sits at the top of Group 1, but it is not a member of that family. Hydrogen is in a class of its own. It is a non-metal, not a metal.

Group 1 – Alkali Metals The alkali family is found in the first column. They are shiny, soft metals that are highly reactive.

Alkali Metals Alkali metals react violently with water and air. They are never found as free elements in nature, they are always in compounds with another element.

Group 2 – Alkaline Earth Metals They are rarely found as single elements in nature. Alkaline earth metals include magnesium and calcium.

Groups 3-12: Transition Metals Transition Elements are probably the metals you are most familiar with: copper, tin, zinc, iron, nickel, gold, and silver. They are good conductors of heat and electricity.

Group 13 – Boron Family This family includes a metalloid (boron), and the rest are metals. The most abundant metal in the Earth’s crust, aluminum, is in this family.

Group 14 – Carbon Family This family includes a non- metal (carbon), metalloids, and metals. The element carbon is called the “basis of life.”

Group 15 – Nitrogen Family The nitrogen family is named after the element that makes up 78% of our atmosphere. This family includes non- metals, metalloids, and metals.

Group 16 – Oxygen Family This family is named after the most abundant element in the Earth’s crust. Oxygen is very reactive and can combine with almost any other element.

Group 17 – Halogen Family Halogens are the most reactive non-metals. They are never found free in nature. They react easily with alkali metals.

Group 18 – Noble Gases Noble Gases are colorless gases that are extremely un-reactive. Because they do not form compounds with other elements, they are called inert. All the noble gases are found in small amounts in the Earth's atmosphere.

Rare Earth Elements The thirty rare earth elements are composed of the lanthanide and actinide series. They fit into the periodic table between the alkaline Earth metals and the transition metals. They are also called the Inner Transition Elements. Many of the rare Earth elements are man-made.

Periods on the Periodic Table Rows going across the periodic table are called periods. Elements in the same period do not share physical and chemical properties. Elements in the same period have the same number of energy levels. Period 1 (n=1) Period 5 (n=5)