Electron Configuration & The Periodic Table Chapter 12

Groups & Periods  Group – vertical column on the periodic table; share similar chemical properties  Period – horizontal rows on the periodic table; give the energy level of the outer electrons  Period 1: H: 1s 1 He: 1s 2  Period 3: Li: [He]3s 1 N: [He]3s 2 3p 3

The Blocks  The periodic table is divided into 4 blocks corresponding to the type of orbital of its outer electrons 1) s-block (groups 1-2) 2) p-block (groups 13-18) 3) d-block (groups 3-12) 4) f-block (Lanthanides & Actinides)

Blocks & e - configuration  Example---need to know Ca configuration  Ca is located in the s-block, on the 4 th period, and the 2 nd column  Using the noble gas that comes before Ca, we can now write Ca configuration just using this info  Ca: [Ar]4s 2

More practice  Oxygen [He]2s 2 2p 4  Vanadium [Ar]4s 2 3d 3 **Watch for d-block, it will always be one less than your row #!

S-Block (Groups 1 & 2) Group 1 is most reactive – Alkali Metals  Has configuration of ns 1  Silvery appearance, but soft Group Alkali Earth Metals  Has configuration of ns 2  Harder, denser, stronger; less reactive

Group 1 and 2 Reactions!

The d-block (groups 3-12)  Elements are known as transition metals  Good conductors of electricity & heat  High luster (shiny) and reactivity decreases as group # increases  Configuration (n-1)d x ns y  transition.html transition.html transition.html

P-block (groups 13-18)  Known as the main group elements  Configuration of ns 2 np x  Include metals, nonmetals & metalloids  Group 16—Chalcogens; purify metals  Group 17—Halogens; react vigorously with metals  Group 18—Noble Gases; inert

F-block  Lanthanides– shiny metals similar with group 2 reactivity  Actinides– all radioactive; only the first 4 are found naturally on Earth; the others only in labs  &q=atomic+bomb&hl=en &q=atomic+bomb&hl=en &q=atomic+bomb&hl=en 