The Periodic Table J. McLeod H. Chemistry

Essential Question How is the periodic table arranged?

A little history… Dmitri Mendeleev: 1st Periodic Table organized the periodic table by increasing atomic mass Left empty spaces Predicted properties of unknown elements

Mendeleev’s Table

A little more history... Henry Moseley: Modern Periodic Table (1887-1915) There were small problems with Mendeleev’s table. Used information he found about isotopes to modify Mendeleev’s table Determined that elements are put in order by their atomic number

Elements are arranged: Vertically into Groups/Families Horizontally Into Periods

Why?

If you looked at one atom of every element in a group you would see… Each atom has the same number of valence electrons Electrons in the outermost energy level (shell)

The group 2 atoms all have 2 electrons in their outer shells Be (Beryllium) Atom Mg (Magnesium) Atom

The number of outer or valence electrons in an atom effects the way an atom bonds. The way an atom bonds determines many properties of the element. This is why elements within a group usually have similar properties.

If you looked at an atom from each element in a period you would see… Each atom has the same number of energy levels.

The period 4 atoms each have 4 energy levels 4th Shell Kr (Krypton) Atom Fe (Iron) Atom K (Potassium) Atom

Divisions of the Table The Periodic Table is divided into regions based on general properties Include: Metals Non-metals Metalloids

Metals Left side of the stairs Forms cations by losing electrons High Melting Points Solids at room temperature (except Hg) Metallic luster Malleable and ductile Good conductors of heat and electricity

Non-metals Right side of the stairs Forms anions by gaining electrons Low Melting Points Gases or solids at room temperature (except Br2) Brittle solids (Which means what?) Insulators (poor conductors or heat & electricity)

Metalloids Have properties of both metals and non-metals Semi-conductors Solids

Ticket Out The Door: State whether the following are metals, nonmetals, or metalloids and then predict a property that they may have: Potassium Iodine Antimony

Bellwork What are the vertical columns of the PT called? What do they have in common? What are the horizontal rows called? What do they have in common?

Groups

Hydrogen Belongs to a family of its own. Is a diatomic, reactive gas. Was involved in the explosion of the Hindenberg. Is promising as an alternative fuel source for automobiles

Alkali Metals Group 1 Soft, silvery colored metals 1 valence e- Very reactive!!!

Alkali Metal Video What trend in reactivity is seen amongst the alkali metals? What would you expect from Francium?!?!

Alkaline Earth Metals Group 2 Silvery-white metals 2 valence e- Fairly reactive Many are found in rocks in the earth’s crust

Transition Metals Most are good conductors heat & electricity Malleable (easily bent or hammered into wires or sheets)

How many things can you think of that have Transition Metals in them? Write as many down as you can in 1 minute.

Halogens Group 17 Have 7 Valence electrons Most are poisonous Cl2 was used as a chemical weapon during WWI and WWII

Halogens What trend in reactivity is seen amongst the Halogens?

Noble Gases Group 18 8 Valence Electrons Very unreactive Gases at room temperature

Jellyfish lamps made with noble gases artist- Eric Ehlenberger

Lanthanides & Actinides Located at the bottom of the Periodic Table Rare Earth Metals Lanthanide Series Actinide Series

Summing it up: Ticket out the Door State which group each of the following elements belongs to and give a property of the element. Lithium Chlorine Uranium Krypton Strontium Chromium

Bellwork What is the most reactive metal? What is the most reactive nonmetal? How many energy levels does Strontium have? How many valence electrons does Aluminum have?

Blank Periodic Table Write the names of the families in their respective columns Alkali Metals, Alkaline Earth Metals, Halogens, & Noble Gases Label the two rows with their respective names Lanthanides & Actinides Outline the metals in RED Outline the metalloids in GREEN Outline the non-metals in BLUE Draw an arrow showing reactivity of METALS Draw an arrow showing reactivity of NONMETALS

Periodicity The properties of the elements on the periodic table create trends as you move around. Trends move left-right & up-down

Reactivity of Metals Towards Francium Inc. down a column Inc. right to left across a period Why? Increase in Size (value of n) Larger in size Increase Shielding effect Weaker nuclear charge Decrease ionization energy Towards Francium Fr

Reactivity of Nonmetals Inc. up a column Inc. left to right across a period Why? Decrease in size (value of n) Smaller in size Decrease Shielding effect Stronger nuclear charge Increase ionization energy F Towards Fluorine

Atomic Radius ½ the distance between two adjacent nuclei …increases as we go down a column WHY? add a new energy level each time …increases as we go right to left across a period Decrease in nuclear charge

Atomic Radii = 1 Angstrom IA IIA IIIA IVA VA VIA VIIA Li Na K Rb Cs Cl P Si Al Br Se As Ge Ga I Te Sb Sn In Tl Pb Bi Mg Ca Sr Ba Be F O N C B 1.52 1.11 1.86 1.60 2.31 1.97 2.44 2.15 2.62 2.17 0.88 0.77 0.70 0.66 0.64 1.43 1.17 1.10 1.04 0.99 1.22 1.22 1.21 1.17 1.14 1.62 1.40 1.41 1.37 1.33 1.71 1.75 1.46 IA IIA IIIA IVA VA VIA VIIA = 1 Angstrom

Ionic Radius the size of an ion cations anions Ca atom Ca+2 ion Cl atom Cl-1 ion 20 p+ 20 p+ 17 p+ 17 p+ 20 e– 18 e– 17 e– 18 e– Cl1– Ca Cl Ca2+ cations lose electrons- smaller Anions gain electrons larger

Atomic Radii Ionic Radii IA IIA IIIA IVA VA VIA VIIA Li Na K Rb Cs Cl S P Si Al Br Se As Ge Ga I Te Sb Sn In Tl Pb Bi Mg Ca Sr Ba 1.52 1.11 1.86 1.60 2.31 1.97 2.44 2.15 2.62 2.17 0.88 0.77 0.70 0.66 0.64 1.43 1.17 1.10 1.04 0.99 1.22 1.22 1.21 1.17 1.14 1.62 1.40 1.41 1.37 1.33 1.71 1.75 1.46 Be B C N O F Atomic Radii 0.60 0.31 0.95 0.65 1.33 0.99 1.48 1.13 1.69 1.35 1.71 1.40 1.36 0.50 1.84 1.81 0.62 1.98 1.85 0.81 2.21 2.16 0.95 Li1+ Be2+ Na1+ Mg2+ Cl1- N3- O2- F1- S2- Se2- Br1- Te2- I1- Al3+ Ga3+ In3+ Tl3+ Ca2+ K1+ Sr2+ Rb1+ Cs1+ Ba2+ Ionic Radii Cations: smaller than parent atoms Anions: LARGER than parent atoms = 1 Angstrom

Ionization Energy Ionization Energy increases the energy required to remove an e– from an atom …increases as we go up a column WHY? shielding effect - increase in the number of energy levels …increases as we go from left to right across a period Nonmetals tend to gain electrons… high 1st ionization energy. Metals tend to lose electrons… low first ionization energy He Ionization Energy increases

Electronegativity electronegativity increases the tendency for a bonded atom to attract electrons to itself …increases as we go up a column …increases as we go left to right across a period WHY? Nonmetals tend to gain electrons… high electronegativity Metals tend to lose electrons… low electronegativity F electronegativity increases

Periodic Table On the periodic table on the next page of your notes… draw out all of the trends if you have not done so already.