Electron Configurations - Cpb-ca-c1.wpmucdn

Electrons in the outermost s and p orbitals.These are the electrons most often involved inbonding.The organization of electrons in an atom or ion,from the lowest energy orbital (“s”)to the highest energy orbital (“f”).spdf

FULL ELECTRON CONFIGURATION: ALL electrons are shown, according to the energylevel and orbital type. Start at n 1 Fill each energy level before moving on to the next.EXAMPLES:1s11s21s2 2s11s2 2s21s2 2s2 2p11s2 2s2 2p51s2 2s2 2p6Noble gases have a FULL VALENCE SHELL,that is, a STABLE OCTET1s2 2s2 2p6 3s2 3p6 4s21s2 2s2 2p6 3s2 3p6 4s2 3d1Note the change in the numbering as you move from 4sto 3d.Note that all of the exponents add up to the atomicnumber of the element.

1s2 2s2 2p6 3s2 3p6 4s2 3d81s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d51s2 2s2 2p6 3s2 3p6 4s2 3d10 4p65s2 4d10 5p6 6s2 4f2Note the change in the numbering as you movefrom 6s element # 56, Bato element #57, La which starts to fill its 4f orbitals.1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p65s2 4d10 5p6 6s2 4f14 5d6Note the change in the numbering as you movefrom 6s element # 56, Bato elements #57 through 70, the Lanthanides, which fillall 14 of the 4f orbitals, and then back up to the5d orbitals that begins with Lu (element # 71) and endswith Hg.(Ac, # 89 to No, # 102 fill their 4f orbitals)(Lr, # 103 to Cn , #112 fill their 6 d orbitals)

CORE ELECTRON CONFIGURATION: Show the electrons in the energylevels past the PREVIOUS noble gas.EXAMPLES:2s12s2 2p54s2 3d84s2 3d10 4p25s2 4d55s2 4d106s2 4f14 5d46s2 4f14 5d10

ORBITAL REPRESENTATION DIAGRAMS:Show the pairs of electrons in each orbital.EXAMPLES:1s22s22p5 1s2 2s22p6 4s2[Ar]3s2 3p6x4s2 4s2 3d10[Ar]6s2 3d8 [Xe] 4f14 4p2 5d4

A “drawing” that represents the nucleus and itsoutermost electrons.Core Electron Config1s1 1s2 [He] 2s1 [He] 2s2 [He] 2s2 2p1 [He] 2s2 2p2 [He] 2s2 2p3 [He] 2s2 2p4 [He] 2s2 2p5 [He] 2s2 2p6 Lewis Dot Diagram

IONS:Atoms usually lose s and p electrons firstsince these are the outermost electrons.EXAMPLES:IONCORE CONFIGURATION[He]2s 2p2LEWIS DOT6Added one electron[Ar]4s2Lost 2 electrons[Ar] 4s23d104p1Lost 3 valence p and then s electrons[Ar] 4s23d104p2[He]2s2 2p6[He]2s 2p62

Sample Lewis dot diagrams for ions:

ELECTRONIC CONFIGURATIONSEXCITED STATE: Atoms absorb energy and existat higher energy levels. As the atom returns to alower energy level, it gives off energy. This relates toemission spectra / spectral lines.Example: Carbon atom.[He][He]2s2 2p 22s1 2p 3 Electron excited from s orbital to a higher energy level.This makes a more stable arrangement, as having allorbitals half filled is more stable than havingsome orbitals with pairs, some with singles, and someempty.This means that C can easily combine with 4 atoms suchas H to make CH4.More on this in Organic Chemistry.

Consider the element GALLIUM, atomic number 31.This neutral (uncharged) element has 31 electrons.We NOW know that each of the electronsexist in complex three dimensionalorbitals:Since Gallium is in the 4 th row of the periodictable:n 40 ℓ n – 1, so ℓ 0, 1, 2, 3, meaning that orbitalsrepresented by EACH of the l values, s, p, d, f, arepossible .(But they may not all be filled by electrons!!!)The mℓ and ms just tell us the orientations in space of theorbitals and the spin of the paired electrons so it is NOTnecessary to look at these each time you write an electronconfiguration.

urface.In fact, the practice that we will do in class will putthis into a more practical approach, rather than themathematical approach as indicated by the quantumnumbers, above.

Full electronic configurationShowing ALL of the electrons in every energylevel from n 1, for Ga:1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1Core electronic configurationShowing electrons of an element, starting at thePREVIOUS noble gas[Ar] 4s2 3d104p1Orbital representation diagramShowing paired electrons with opposite spins, ineach orbital:

Some textbooks, and even teacher worksheets, show fullelectron configurations as ENERGY DIAGRAMS, so that theenergy differences of the electrons in each level is clearlydemonstrated:

Practice done in class, with the teacher, on the white board,is essential for the understanding of electron configurations.We will start with basic FULL configurations, understanding theprogression of the electron configurations from Hydrogen to Helium toLithium, to Beryllium, etc.We will learn how to best distribute electrons in p orbitals so that weknow when to have paired and unpaired electrons.As we enter the 3rd energy level, and d orbital electrons are possible, itis necessary to understand how to write the MOST STABLE electronconfigurations.And entering the 4th energy level, which introduces f orbital electrondistributions, we must understand how an element would fill it’s orbitalsin the proper energy level order.Practice in class will be accompanied by three dimensional images andvideos on screen, as well has examples of emission spectra, so that youcan understand this work that you are doing, IN CONTEXT.The sample questions will evolve organically, as we developunderstanding of each aspect, so providing a full notes package on thepractice questions would not be beneficial to your understanding, nor isit possible to predict each question in the order it will be presented.Once we are comfortable, we will also introduce ions, so that weunderstand WHERE an element would lose or gain electrons from, inorder to achieve the most stable configuration.This will lead us into the ionic and covalent (molecular) bonding that wewill be studying next.You will learn better by being able to work through this unit inconsultation with your lab partners.

FULL ELECTRON CONFIGURATION: ALL electrons are shown, according to the energy level and orbital type. Start at n 1 Fill each energy level before moving on to the next. EXAMPLES: 1s1 1s2 1s2 2s1 1s2 2s2 1s2 2s2 2p1 1s2 2s2 2p5 1s2 2s2 2p6 Noble gases have a FULL VALENCE SHELL, th