Write the Complete Electron Configuration for: Warm Up Write the Complete Electron Configuration for: Lithium, Li Sodium, Na Rubidium, Rb

Electron Configuration and Periodic Properties Periodic Trends Electron Configuration and Periodic Properties

Periodic Trends The Groups and Periods of the Periodic Table display predictable trends that include: Atomic Radius Ionization Energy Electronegativity

Atomic Radius Atomic Radius refers to the size of the atom; it is the distance from the center of the nucleus to the “edge” of the outermost energy level.  

Atomic Radius Atomic Radius increases to the LEFT and DOWN

Atomic Radius Increases DOWN (↓) a Group Higher energy levels have larger orbitals Shielding – core e- block the attraction between the nucleus and the valence e- Decreases RIGHT (→) across a Period Stronger Nuclear Charge (more p+) without additional shielding (shells) pulls e- in tighter.

     

Shielding Shielding refers to the reduced attraction felt between the outer shell electrons and nucleus due to the ‘shielding’ effect of the inner shell electrons. The nuclear charge felt by the outer shell electrons is much less compared to that of the inner shell electrons, and are therefore held less tightly held.

Nuclear Charge As we move left to right across a period, more p+ and e- are added to the existing energy levels. The nucleus is more positive (+) and the e- cloud is more negative. The Nuclear Charge is the pull that the (-) e-“feels” from the (+) nucleus. The increased attraction pulls the cloud in, making atoms smaller.

Atomic Radius Practice Which of the following elements has the largest atomic radius: Li, O, C, or F? Which has the smallest radius? Li, F

Atomic Radius Practice Of the elements P, Mg, Ca, and Ba, which has the largest atomic radius? Which has the smallest? Ba, P

Atomic Radius Practice Arrange the following elements in order of increasing Atomic Radii. Al, Ar, Cs, Na Ar, Al, Na, Cs

Atomic Radius Draw arrows like this on your handout and explain the Atomic Radii Trend in your own words:

Ionization Energy Ionization Energy is the energy required to remove an electron from an atom.

Ionization Energy Ionization Energy Increases UP and to the RIGHT

Ionization Energy Ionization Energy is the opposite of Atomic Radius….As (A.R.) decreases, (I.E.) increases, and vice versa. Why? As atoms get smaller, the e- get closer to the (+) nucleus where there is a greater Nuclear Charge (attraction) between them. As atoms get larger, the e- get farther from the nucleus, making them easier to remove. More ‘Shielding’ Lower Nuclear Charge

Ionization Energy Practice Which of the following elements has the largest Ionization Energy: O, C, Be, or Ne? Which has the smallest? Ne, Be

Ionization Energy Practice Of the elements Ca, Ba, Mg, and Ra, which has the largest Ionization Energy? Which has the smallest? Mg, Ra

Ionization Energy Practice Arrange the following elements in order of increasing Ionization Energy. Mg, B, Cl, K K, Mg, B, Cl

Ionization Energy (Potential) Draw arrows like this on your handout and explain the Ionization Energy Trend in your own words:

Electronegativity Compounds form because electrons are lost, gained, or shared between atoms. The e- available to do this are called “Valence Electrons”. They are the outermost electrons. Electronegativity is the tendency of an atom to attract electrons towards itself.

Electronegativity Electronegativity Increases UP and to the RIGHT

Electronegativity Follows the same trend as Ionization Energy. Why? Smaller atoms are more electronegative due to the stronger force of attraction between their own e- and those belonging to other atoms.

Electronegativity Practice Which of the following elements has the largest Electronegativity: Cs, N, Si, or K? Which has the smallest? N, Cs

Electronegativity Practice Of the elements Na, Rb, O, and Fr, which has the largest Electronegativity? Which has the smallest? O, Fr

Electronegativity Practice Arrange the following elements in order of increasing Electronegativity. Al, Ba, N, C Ba, Al, C, N

Electronegativity Draw arrows like this on your handout and explain the Electronegativity Trend in your own words: