Electron Configuration A Closer Look at Electrons

Where are they in the Atoms? Located within energy levels Energy levels range from 1-7 Higher energy levels The electron (e-) is farther from the nucleus The more energy the e- has

Energy Level Changes An electron absorbs energy to “jump” to a higher energy level. When an electron falls to a lower energy level, energy is emitted. In the visible range, the emitted energy appears as a color. LecturePLUS Timberlake

Electron Energy Levels Electrons are arranged in specific energy levels that are labeled n = 1, n = 2, n = 3, and so on increase in energy as n increases have the electrons with the lowest energy in the first energy level (n = 1) closest to the nucleus LecturePLUS Timberlake

Within each energy level There are sublevels that differ by slight differences in energy There are four sublevels S, P, D, F Within each sublevel are paths called Orbitals

Number of Sublevels LecturePLUS Timberlake

Orbitals S sublevels, there is 1 orbital, which holds a total of 2 e- P sublevels, there are 3 orbitals, holding a total of 6 e- D sublevels, there are 5 orbitals, holding a total of 10 e- F sublevels, there are 7 orbitals, holding a total of 14 e-

Writing The e- configuration 1s2 1 = the energy level S = the sublevel or orbital 2= the number of electrons

What order do orbitals fill? Orbitals Fill in this order Number of this type of orbital Total # of electrons 1s 1 2 2s 2p 3 6 3s 3p 4s 3d 5 10 4p

How to write an e- configuration Locate the element on the periodic table. 2. Fill the orbital in the proper order. 3. Check that the total # of e- you have equals the atomic # for that element

Complete filling order 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

Orbitals An orbital is a three-dimensional space around a nucleus where an electron is most likely to be found has a shape that represents electron density (not a path the electron follows) can hold up to 2 electrons contains two electrons that must spin in opposite ↑↓ LecturePLUS Timberlake

s Orbital's An s orbital has a spherical shape around the nucleus increases in size around the nucleus as the energy level n value increases is a single orbital found in each s sublevel LecturePLUS Timberlake

p Orbitals A p orbital has a two-lobed shape is one of three p orbitals that make up each p sublevel increases in size as the value of n increases LecturePLUS Timberlake

Sublevels and Orbitals Each sublevel consists of a specific number of orbitals. An s sublevel contains one s orbital. A p sublevel contains three p orbitals. A d sublevel contains five d orbitals. An f sublevel contains seven f orbitals. LecturePLUS Timberlake

Practice problems Write the electron configuration for the following elements Carbon (C) Lithium (Li) Sodium (Na) Chlorine (Cl) Potassium (K) Iron (Fe)

Chemistry 111/112 Chapter 9 Orbital Diagrams An orbital diagram represents each orbital with a box, with orbital's in the same subshell in connected boxes; electrons are shown as arrows in the boxes, pointing up or down to indicate their spins. REMEMBER:Two electrons in the same orbital must have opposite spins. ↑↓ Copyright (c) 2003 Thomson Learning Reprinted with permission 1