How the periodic table is put together

What is the Periodic Table? It is an organizational system for elements.

Who created it?   By 1860 about 60 elements were known and a method was needed for organization.  In 1869, Russian chemist Dimitri Mendeleev proposed arranging elements by atomic weights and properties. The table contained gaps but Mendeleev predicted the discovery of new elements.

So how is it arranged? The periodic table is organized in a grid. The elements are placed in specific places because of the way they look and act. There are rows (left to right) and columns (up and down) , and they each mean something different.

You've got Your Periods... Each row is considered to be a different period (Get it? Like PERIODic table.) Even though they skip some squares in between, all of the rows go left to right.

Periods = Rows In the periodic table, 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 shells/orbitals. Every element in the top row (the first period) has one shell for its electrons. All of the elements in the second row (the second period) have two shells for their electrons. It goes down the periodic table like that.

As you move down through the periods an extra electron shell is added: E.g. Lithium has 3 electrons in the configuration 2,1 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg Sodium has 11 electrons in the configuration 2,8,1 Potassium has 19 electrons in the configuration __,__,__, __ 2 8 8 1

And you got your groups… The periodic table has a special name for its columns too. When a column goes from top to bottom, it's called a group.

Groups = Columns The elements in a group have the same number of Valence electrons. Every element in the first column (group 1) has one valence electron in its outer shell. Every element on the second column (group two) has two valence electrons in the outer shell. There are some exceptions to the order when you look at the transition elements

Elements in the same group have the same number of electrons in the outer shell (this correspond to their group number) H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Fe Ni Cu Zn Br Kr Ag I Xe Pt Au Hg These elements have __ electrons in their outer shells These elements have __ electrons in their outer shell All group 1 metals have __ electron in their outer shell

What do all the numbers mean?

Some Symbols don’t match their name: Sodium – Na Potassium - K  Iron - Fe  Copper - Cu  Silver - Ag  Tin - Sn  Antimony – Sb Tungsten – W Gold - Au  Mercury - Hg  Lead - Pb QUIZ ON TUESDAY 9/15

Other than periods and groups, the table is divided into families. Elements in each family react differently with other elements. Each family has a specific name to differentiate it from the other families in the periodic table.

Hydrogen is not a member, it is a non-metal ALKALI METALS Hydrogen is not a member, it is a non-metal HIGHLY reactive due to having 1 valence electron Metals- Solid @ Room temp malleable, ductile, good conductors of heat and electricity. can explode if they are exposed to water COLOR BLUE

ALKLINE EARTH METALS Metals- Solid @Room Temp 2 valence electrons White, silvery, and malleable Reactive, but LESS than Alkali metals COLOR RED

TRANSITION METALS COLOR YELLOW Metals Almost all are solids at room temp (except Hg) Good conductors of heat and electricity. 1 or 2 Valence Electrons Less Reactive than Alkali and Alkaline Earth COLOR YELLOW

RARE EARTH ELEMENTS many are man-made Some are Radioactive COLOR GREY

OTHER METALS are ductile and malleable are solid, have a high density COLOR LIGHT BLUE

METALLOIDS COLOR PURPLE have properties of both metals and non-metals Some of the metalloids are semi-conductors. This means that they can carry an electrical charge under special conditions. This property makes metalloids useful in computers and calculators COLOR PURPLE

NON-METALS COLOR GREEN Hydrogen is included!!! Not able to conduct electricity or heat very well Very Brittle COLOR GREEN

HALOGENS COLOR PINK 7 electrons in the outer shell Non-metals Very reactive - are often bonded with Group 1 Alkali Metals Has 2 gases, 1 liquid (Br), and 2 solids COLOR PINK

NOBLE GASES COLOR ORANGE Group 8 Exist as gases Non-metals 8 electrons in the outer shell = Full Helium (He) has only 2 electrons in the outer shell = Full Not reactive with other elements COLOR ORANGE