The Periodic Table of Elements Chapter 17.5 and 17.6

Who made it? The first periodic table was constructed by a Russian Chemist, Dmitri Mendeleev, in 1869 Mendeleev arranged the elements in his table according to their atomic mass. This was later changed to atomic number which is the way it is arranged today.

The Periodic Table Mendeleev arranged the elements in such a way that the elements with similar properties were in the same column. The columns are called groups Elements found in the same column are said to be in the same group. The rows are called periods Elements found in the same row are said to be in the same period

The Periodic Table Group 1 Group 2 1st Period 2nd Period 3rd Period

Why is it set up this way Mendeleev created his periodic table in this way because he noticed patterns occurring with the elements. Because he set up his table based on the patterns he noticed, Mendeleev left blank spaces in which he was able to predict the properties of elements that had yet to be discovered. His table was proven useful when these elements were discovered and had properties that were a close match to his predictions

Mendeleev's Periodic Table

The Modern Periodic Table The Modern Periodic table is not arranged by atomic mass, but by atomic number Atomic number = number of protons Mendeleev did not know about protons in 1872 There are 18 groups on the periodic table and 7 periods

The Modern Periodic Table The majority of the Elements found on the periodic table are metals Metals are shiny, opaque, and are good conductors of electricity and heat Many of them are malleable, meaning they can be hammered into shape or bent with out breaking They are also ductile, which means they can be drawn into wire. Most are solid at room temperature except for Mercury (Hg), Gallium (Ga), Cesium (Cs), and Francium (Fr).

The Metals

The Periodic Table All of the non metal elements are found on the right of the Periodic Table, except for Hydrogen. Non metals are very poor conductors of electricity and heat. They are brittle and shatter when hammered.

The Non-metals

The Modern Periodic Table The modern Periodic Table has a line that separates the metals from the non-metals. This line is often referred to as the staircase.

The Modern Periodic Table The modern Periodic Table has a line that separates the metals from the non-metals. This line is often referred to as the staircase. To the left of the stair case are the metals (except Hydrogen!)

Metals NOT HYDROGEN!

The Periodic Table The modern Periodic Table has a line that separates the metals from the non-metals. This line is often referred to as the staircase. To the left of the stair case are the metals (except Hydrogen!) To the right of the stair case are the non metals. Don’t forget Hydrogen!

Non- Metals Metals

The Periodic Table The modern Periodic Table has a line that separates the metals from the non-metals. This line is often referred to as the staircase. To the left of the stair case are the metals (except Hydrogen!) To the right of the stair case are the non metals. Don’t forget Hydrogen! Along the stair case are a special group called metalloids

Metalloids have some characteristics of metals and some characteristics of non metals They are in-between metals and non metals

The Atom and The Periodic Table Aside from metals and non metals the periodic table is organized in two ways. These two ways are in Groups/Families Periods

Rows on the Table Remember, the atomic number = the number of electrons. The first row has Hydrogen with one electron and Helium with two electrons both in energy level one. Therefore, Helium has the first energy level full. We consider this as being stable.

Rows on the Table If you look at the second row, it starts with lithium and ends with neon. Lithium has three electrons and neon has ten electrons. Lithium has two electrons in the first shell and one in the second. Neon has two electrons in the first shell and eight in the second. The first column always starts the new shell. The last column always fills the shell.

Groups Groups or families are the vertical columns on the periodic table. Groups are numbered 1 through 18. These elements have the same number of electrons in their outer orbits. Valence Electrons! They also have many characteristics in common. The group IIa elements; beryllium, magnesium, calcium, strontium, & barium. They are called the Alkali Earth Metals.

Alkali Metals The first group of elements on the periodic table are called The Alkali Metals

Alkali Metals

Alkali Metals The first group of elements on the periodic table are called The Alkali Metals The Alkali Metals are very reactive Many of them like sodium react violently with water As you move down the group they become more and more reactive

Alkaline Earth Metals The second group on the periodic table are called Alkaline Earth Metals

Alkaline Earth Metals

Alkaline Earth Metals The second group on the periodic table are called Alkaline Earth Metals Alkaline Earth Metals react with water but not as violently as Alkali Metals Alkaline Earth Metals also do not melt or change when placed in fire

Transition Metals Group 3 through 12 are known as the Transition Metals

Transition Metals

Transition Metals Group 3 through 12 are known as the Transition Metals Transition metals are the more familiar metals such as copper, gold, silver, iron, nickel, and chromium. These metals are usually shiny, do not react well with water, and melt when heated

Inner Transition Metals The inner transition metals belong in the 6th and the 7th period

Inner Transition Metals

Inner Transition Metals The inner transition metals belong in the 6th and the 7th period The Lanthanide Series belongs in the 6th period because of its properties the Actinide Series belongs in the 7th period because of its properties Inserting them into the Periodic Table would make a long periodic table that wouldn’t fit on a piece of paper! Uranium, an actinide, is used in nuclear power plants

Groups 13-16 Groups 13-16 have no common names but contain many elements familiar to us. Boron, Carbon, Nitrogen, & Oxygen can all be found in groups 13 through 16 Since they don’t have a special name we just use the first element in the group as the name ie. Boron Group Each member of the group has the same number of valence electrons Some of these elements are metals, metalloids or non-metals depending on where they are found relative to the stair case

Boron Group Carbon Group Nitrogen Group Oxygen Group

Halogens Group 17 are known as the Halogens

Halogens

Halogens Group 17 are known as the Halogens Halogens in Greek mean “salt forming” Many elements in this group form salts with metals Ie. Sodium Chloride Some Halogens such as Bromine and Iodine are found in Halogen lamps which glow brighter without burning out quickly Chlorine is a Halogen

The Noble Gases Group 18 are known as the Noble Gases

Noble Gases

The Noble Gases Group 18 are known as the Noble Gases The noble gases do not react with any other elements or themselves They are chemically stable or unreactive They get their name from the Nobles who would never interact with the common folk!