15 Electron Placement Use with Chapter 7, Section 7.2 3p 3s _ _ _ _ _ _ _ _ _ _ Copyright © Glencoe / McGraw - Hill, a division of The McGraw - Hill Companies, Inc. 2p 2s 1s Nucleus In what ways is the bricklayer limited in the order in which he sets layers of brick and in the numbers of bricks? In what ways are electron placements limited in the energy levels of atoms? Chemistry: Concepts and Applications Transparency 15