Chapters 8, 21, and 22 THE PERIODIC TABLE

 4.7 Explain the history and development of the periodic table.  4.8 Utilize periodic tends to predict the properties of elements.  4.9 Write the electron configuration for ions.  4.10 Explain the properties of metals and nonmetals. OBJECTIVES

 First organized using atomic masses.  Mendeleev organized the periodic table based on grouping elements with similar properties together.  Was able to predict the existence of Gallium  This pointed out inconsistencies with ordering elements based on their atomic mass.  Later, the periodic table was reorganized by increasing atomic mass, which explained these inconsistencies. THE DEVELOPMENT OF THE PERIODIC TABLE

OTHER VERSIONS OF THE PERIODIC TABLE

PERIODIC TRENDS

 Good conductors of electricity and heat  Shiny, malleable, and ductile  Solid at room temperature  Metallic character of metals increases to the right and up on the periodic table. PROPERTIES OF METALS

 Can be solid, liquid, or gas at room temperature  Poor conductors of heat and electricity  Can for an anion or cation  Do not have luster  Are not malleable or ductile PROPERTIES OF NONMETALS

PERIODIC TRENDS

 For Main Group Elements  Electrons are removed or added to the s and p orbitals until the element has the same electron configuration as the nearest noble gas element.  For Transition Metals  Electrons are removed from the outermost s orbital before they are removed from the d orbital.  This is because it is more energetically favorable and stable to remove the electrons in the s shell before those in the d.  Isoelectronic  Refers to elements with the same ground-state electron configuration  Also have the same number of electrons ELECTRON CONFIGURATION OF CATIONS AND ANIONS

 Na +1  Al +3  P -3  Sn +4  Sn +2 WRITING ELECTRON CONFIGURATIONS FOR IONS

 Effective Nuclear Charge  The nuclear charge felt by an electron when both the actual nuclear charge and the shielding effect of the other electrons are taken into account.  Increases to the right and down on the periodic table.  Atomic Radius  Half the distance between two nuclei in two adjacent metal atoms  Increases to the left and down on the periodic table PERIODIC TRENDS

 Ionic Radius  The radius of an ion  Increases moving down a group on the periodic table  Elements that form 3+ cations have a smaller radius than those that form 1+ cations  Elements that form a 2- anion have a larger radius than those that form a 1- anion PERIODIC TRENDS

Effective Nuclear Charge Atomic Radius Ionic Radius

 Na or O  K or Rb  P or S  Si or F  Cl or Br  Ca or C WHICH OF THE FOLLOWING ELEMENTS HAS THE LARGEST EFFECTIVE NUCLEAR CHARGE/ATOMIC RADIUS?

 Na +1 or O -2  K +1 or Rb +1  P -3 or S -2  Si +4 or F -1  Cl -1 or Br -1  Ca +2 or C +4 WHICH OF THE FOLLOWING HAS THE LARGEST IONIC RADIUS?

WHAT ARE YOUR QUESTIONS?

 Ionization Energy  The minimum energy (in kJ/mole) required to remove an electron from a gaseous atom in it’s ground state.  Indicates how “tightly” an atom holds onto its own electrons.  Increases up and to the right on the periodic table.  The higher the ionization energy, the more stable the atom.  First Ionization Energy  The amount of energy required to removed the first electron from the ground state of an atom.  Ionization energy increases for each subsequent electron removed from an atom. PERIODIC TRENDS

 Electron Affinity  The ability for an atom to accept electrons from other atoms.  Positive if exothermic process  Negative if endothermic process  Values increase from left to right across a period  Metals have a lower electron affinity than non-metals  Values vary little within a group; however, halogens have the highest electron affinity. PERIODIC TRENDS

Ionization Energy Electron Affinity

 Na or O  K or Rb  P or S  Si or F  Cl or Br  Ca or C WHICH OF THE FOLLOWING ELEMENTS HAS THE SMALLEST FIRST IONIZATION ENERGY?

 Na or O  K or Ca  P or S  Si or F  Cl or Al  Li or C WHICH OF THE FOLLOWING ELEMENTS HAS THE LOWEST ELECTRON AFFINITY?

PERIODIC TRENDS

 Knowing the periodic trends helps predict how certain elements/compounds will react.  Elements within the same group have similar electron configurations and will therefore have similar properties.  The first element in each group is usually a little atypical since its atomic size is so small compared to the other members of the group.  Diagonal Relationship  Similarities between pairs of elements in different groups/periods in the periodic table due to similarities in charge density.  Examples: Li and Mg, Be and Al, B and Si MAIN GROUP ELEMENT PROPERTIES

 Group trends hold true best for groups 1 and 2 and also 7 and 8.  Since groups 3 through 6 are a mix of metals and nonmetals, group trends aren’t as prominent/dependable.  Hydrogen  Can be included in groups 1 or 7 since it can form either H + or H - ions (HCl or CaH 2 ).  Ionic hydrides will react with water to produce a base and hydrogen gas. CaH 2(s) + 2H 2 O (l)  Ca(OH) 2(aq) + 2H 2(g) MAIN GROUP ELEMENT PROPERTIES

 Have low ionization energies, so tend to form cations.  Are so reactive that they are not found in their pure state in nature.  Produce metal hydroxides when reacted with water.  Form oxides, peroxides, or superoxides (contain O 2 - ) when reacted with oxygen gas. 4Li (s) + O 2(g)  2Li 2 O (s) 2Na (s) + O 2(g)  Na 2 O 2(s) K (s) + O 2(g)  KO 2(s)  The type of oxide that forms is dependent on the stability of the ion in the solid state. PROPERTIES OF ALKALI METALS

 Less reactive that the alkali metals.  Tend to form 2+ ions.  Metallic properties of the group increase down the column.  Reacts with water to form metal hydroxides. Ca (s) + H 2 O (l)  Ca(OH) 2(aq) + H 2(g)  Reacts with oxygen gas to form metal oxides. 2Ca (s) + O 2(g)  2CaO (s)  Reactivity with water and oxygen increases going down the group.  Reacts with acids to produce hydrogen gas. PROPERTIES OF ALKALINE EARTH METALS

 Made up of a metalloid and metals.  Boron and Aluminum will form 3+ ions; however, the other elements in this group can form 1+ and 3+ ions.  Aluminum will react with acids to produce hydrogen and oxygen to form a metal oxide. PROPERTIES OF GROUP 3 ELEMENTS

 Comprised of metals, nonmetals, and metalloids.  Tin and Lead will react with acids to produce hydrogen gas. Sn (s) + HNO 3(aq)  Sn(NO 3 ) 2(aq) + H 2(g)  Carbon and Silicon tend to form a 4+ oxidation state; however, the other elements can from +2 or +4 with the 2+ oxidation state being the more stable. PROPERTIES OF GROUP 4 ELEMENTS

 Includes nonmetals (N and P), metalloids (As and Sb), and metals (Bi).  Nitrogen and phosphorus tend to form a 3- oxidation state. Varies for the other elements.  Oxides of nitrogen and phosphorus will react with water to make oxoacids. N 2 O 5(s) + H 2 O (l)  2HNO 3(aq) P 4 O 10(s) + 6H 2 O (l)  4H 3 PO 4(aq) PROPERTIES OF GROUP 5 ELEMENTS

 Made of nonmetals (O,S, and Se) and metalloids (Te and Po).  Tend to form a 2- oxidation state.  Form a lot of compound with other nonmetals.  Polonium is radioactive. PROPERTIES OF GROUP 6 ELEMENTS

 Nonmetals that tend to bond with themselves.  Form a 1 - oxidation state.  Very reactive with other elements.  Not found in elemental form in nature.  Have high ionization energies and electron affinities.  Bonds with alkali metals and alkaline earth metals to form ionic compounds.  React with hydrogen to produce hydrogen halides. H 2(g) + Cl 2(g)  2HCl (g) PROPERTIES OF HALOGENS

 Have completely filled outer shells, so do not easily bond with other elements.  Typically exist as a monoatomic gas.  A few compounds have been made using Xenon and Krypton, but they are prepared in the laboratory. PROPERTIES OF THE NOBLE GASES

 Considered “the bridge” of the periodic table.  These elements are very hard, with high melting points and boiling points and have low ionization energies.  Form cations but with varying oxidation states.  Readily undergo redox reactions.  The electrons located in the d shell of transition metals are loosely bound, which contributes to the high electrical conductivity and malleability of transition metals. PROPERTIES OF THE TRANSITION METALS

THE LANTHANIDES AND ACTINIDES

  Also known as the Rare Earth Metals  Cerium is the 26th most abundant element in the Earth's crust, neodymium is more abundant than gold and even thulium  Fill the f subshell  Form varying oxidation states, but typically are cations. PROPERTIES OF LANTHANIDES

 Fill the f subshell  Are radioactive and release energy when the decay.  Thorium and uranium occur naturally in substantial quantities and small amounts of natural plutonium have also been identified. These are also used in nuclear reactors.  The radioactive decay of uranium produces small amounts of protactinium and neptunium; however, all other actinides are purely synthetic.  Other actinides, such as americium, curium, berkelium, californium, einsteinium, and fermium have been detected as a results of nuclear weapons tests. PROPERTIES OF ACTINIDES

 Oxide  Compound containing oxygen  Properties can very greatly depending on what oxygen is bonding with.  Forms ionic compound when it bonds with elements from groups 1 or 2 and aluminum.  Forms covalent compounds with nonmetals.  Exhibit properties of acids or bases Na 2 O (s) + H 2 O (l)  2NaOH (aq) MgO (s) + 6HCl (aq)  MgCl 2(aq) + H 2 O (l)  Nonmetal oxides tend to be acidic  Amphoteric  Exhibits both acidic and basic properties Al 2 O 3(s) + 6HCl (aq)  2AlCl 3(aq) + H 2 O (l) Al 2 O 3(s) + 2NaOH (aq) + 2H 2 O (l)  2NaAl(OH) 4(aq) PROPERTIES OF OXIDES

WHAT ARE YOUR QUESTIONS?