Chemistry Chapter Chemistry Chapter 5&65&6

The Periodic Law Notes The Periodic Law Notes 55

Mendeleev’s Periodic Table

Dmitri Mendeleev

Modern Russian Table

Chinese Periodic Table

Stowe Periodic Table

A Spiral Periodic Spiral Periodic TableTable

Triangular Periodic Table

““Mayan” Mayan”

Periodic Periodic TableTable

Orbital filling table

Periodic Table with Group Names

Easily lose valence electron (Reducing agents)

React violently with water Large hydration energy React with halogens to form

salts

The Properties of a Group: the Alkali Metals

Sublevel Blocks of the Periodic TableSublevel Blocks of the Periodic Table

Figure 5-5 p. 129

ss-block-block• Group 1Group 1• Alkali MetalsAlkali Metals

– nnss11 is highest level is highest level

– Silvery appearanceSilvery appearance

– Soft—cut with knifeSoft—cut with knife

– Highly reactive—never Highly reactive—never found free in naturefound free in nature

– Low melting points Low melting points <100<100ooCC

• Group 2Group 2• Alkaline-earth metalsAlkaline-earth metals

– nnss22 is highest level is highest level

– Harder & denser, w/ Harder & denser, w/ higher melting points higher melting points than Group 1than Group 1

– Highly reactive—never Highly reactive—never found free in naturefound free in nature

Special exceptions to Special exceptions to ss-block-block• HydrogenHydrogen

– Has nHas nss11

– Totally different Totally different properties from alkali properties from alkali metalsmetals

• HeliumHelium– Has nHas nss22

– Highest level is Highest level is completely fullcompletely full

– Stable like noble gasesStable like noble gases

dd-block-block• dd sublevel for preceding energy level is filling sublevel for preceding energy level is filling• dd sublevel filling has some deviations—Group 11: sublevel filling has some deviations—Group 11:

Cu, Ag, Au Cu, Ag, Au – Outer Outer ss & & dd sublevels still have same # e sublevels still have same # e--

• Transition elements: d-block metals w/ typical Transition elements: d-block metals w/ typical metallic propertiesmetallic properties– Less reactive than Group 1 & 2Less reactive than Group 1 & 2

– Exist free in natureExist free in nature

– Good conductors of electricityGood conductors of electricity

– High luster (shiny)High luster (shiny)

pp-block-block• All elements of Groups 13-18 except HeliumAll elements of Groups 13-18 except Helium• Properties vary greatlyProperties vary greatly• Nonmetals (right hand end)Nonmetals (right hand end)• All six metalloidsAll six metalloids

– Brittle solidsBrittle solids– Some properties of metals and nonmetalsSome properties of metals and nonmetals

• Eight metals (left hand side and bottom of the block)Eight metals (left hand side and bottom of the block)– Harder and denser then s-block alkaline-earth metalsHarder and denser then s-block alkaline-earth metals– Softer and less dense than d-block metalsSofter and less dense than d-block metals– Stable in the presence of airStable in the presence of air

• Group 17 HalogensGroup 17 Halogens– Most reative of the nonmetalMost reative of the nonmetal– 7 electrons in outer shell7 electrons in outer shell

ff-block-block• Lanthanides & ActinidesLanthanides & Actinides• 14 elements—seven 414 elements—seven 4ff orbitals are filling orbitals are filling• LanthanidesLanthanides

– Similar reactivity to Group 2Similar reactivity to Group 2– Shiny metalsShiny metals

• ActinidesActinides– Only 1Only 1stst four found in nature four found in nature– All are radioactiveAll are radioactive

Half of the distance between nucli in covalently bonded diatomic molecule

"covalent atomic radii"

Periodic Trends in Atomic Radius

Radius decreases across a period Increased effective nuclear charge dueto decreased shielding

Radius increases down a group Addition of principal quantum levels

Determination of Atomic Radius:

Table of Table of Atomic Atomic

RadiiRadii

Increases for successive electrons taken from the same atom

Tends to increase across a period

Electrons in the same quantum level do not shield as effectively as electrons in inner levels

    Irregularities at half filled and filled sublevels due to extra repulsion of electrons paired in orbitals, making them easier to remove

Tends to decrease down a groupOuter electrons are farther from thenucleus

Ionization Energy - the energy required to remove an

electron from an atom

Ionization of Magnesium Mg + 738 kJ Mg+ + e-

Mg+ + 1451 kJ Mg2+ + e-

Mg2+ + 7733 kJ Mg3+ + e-

Table of 1st Ionization Energies

Another Way to Look at Ionization Energy

Affinity tends to increase across a period

Affinity tends to decrease as you go down in a Group or family

Electrons farther from the nucleusexperience less nuclear attraction

Some irregularities due to repulsive forces in the relatively small p orbitals

Electron Affinity - the energy change associated with the addition of an electron

Table of Electron AffinitiesTable of Electron Affinities

Ionic RadiiIonic RadiiCations

Positively charged ions Smaller than the

corresponding atomAnions

Negatively charged ions Larger than the corresponding atom

Summation of Periodic Trends

Table of Ion Sizes

ElectronegativityElectronegativity

A measure of the ability of an atom in a chemicalcompound to attract electrons

Electronegativities tend to increase across a period

Electronegativities tend to decrease down a group or remain the same

Periodic Table of Electronegativities