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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.
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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 absorbsenergy 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.
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) closestto the nucleus
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
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
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 ↑↓
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
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
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.
Practice problems • Write the electron configuration for the following elements • Carbon (C) • Lithium (Li) • Sodium (Na) • Chlorine (Cl) • Potassium (K) • Iron (Fe)
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.