Periodic Trends

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Periodic Trends : 

Periodic Trends Metallic nature of elements increases towards the: Right or Left? Top or Bottom? Properties and position of elements on PT are due to the electron configuration of the atoms.

Radii of Atoms : 

Radii of Atoms Atomic radius – radius of an atom without regard to surrounding atoms As you go down the Periodic Table, the atomic size increases. Within a period from leftright , the total (+) charge of nucleus is increasing  pulls electrons in closer

Radii of Ions : 

Radii of Ions Atoms are more stable in compounds than they are alone…why? Ionic radii – radius of an ion when electrons have been gained or lost Metal ions are smaller than metal atoms Nonmetal ions are larger than nonmetal atoms

Summary of Ions: : 

Summary of Ions: Metallic ions Gain or lose electrons? Larger or smaller than atoms? Nonmetallic ions Gain or lose electrons? Larger or smaller than atoms?

Ionization Energy : 

Ionization Energy To “react”, atoms must give up or take on electrons Requires energy Ionization energy is the energy required to remove an electron from an atom

Periodic Trend: 1st Ionization Energy : 

Periodic Trend: 1st Ionization Energy 1st Ionization Energy: Energy required to remove the most loosely held electron (“last” electron) Trend 1st Ionization Energy increases as you go Up & Right

More Rules of Thumb… : 

More Rules of Thumb… Metals generally have low 1st I.E. Nonmetals generally have high 1st I.E. Magnitude of I.E. is affected by 4 factors

4 factors affecting Ionization Energy magnitude: : 

4 factors affecting Ionization Energy magnitude: Nuclear Charge – larger the + charge in nucleus, larger the I.E. Shielding effect – greater the number of e- between loosest held e- & nucleus, smaller the I.E. Radius – greater distance from nucleus to outer e- level, smaller the I.E. Sublevel filling – e- from a filled or half-filled sublevel requires add’l energy to be removed

Why are there dips? : 

Why are there dips?

Electronegativity : 

Electronegativity Electronegativity – the relative attraction an atom has for electrons in a bond In a free atom, this attraction is referred to as electron affinity Electronegativity (and electron affinity) will increase as you go right (increased nuclear charge) up (smaller radius, less shielding effect)

Periodic Trends Summarized : 

Periodic Trends Summarized Image courtesy of http://upload.wikimedia.org/wikipedia/en/4/40/PERIODIC_TRENDS2.jpg

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