bromine (Br) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 21. Write ground-state electron configurations for the following elements. (Orbital Diagrams) bromine (Br) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ 4s2 3d10 4p5 1s22s22p63s23p64s23d104p5 [Ar]4s23d104p5 4s24p5 4p5

strontium (Sr) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4s2 3d10 4p6 5s2 1s22s22p63s23p64s23d104p6 5s2 [Kr]5s2 5s2 5s2

antimony (Sb) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4s2 3d10 4p6 5s2 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑ 4d10 5p3 1s22s22p63s23p64s23d104p6 5s24d105p3 [Kr]5s24d105p3 5s25p3 5p3

rhenium (Re) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4s2 3d10 4p6 5s2 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4d10 5p6 6s2 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ ↑ ↑ ↑ ↑ 4f14 5d5 1s22s22p63s23p64s23d104p6 5s24d105p66s24f145d5 [Xe]6s24f145d5 6s25d5 5d5

terbium (Tb) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4s2 3d10 4p6 5s2 ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4d10 5p6 6s2 ↑↓ ↑↓ ↑ ↑ ↑ ↑ ↑ 4f9 1s22s22p63s23p64s23d104p6 5s24d105p66s24f9 [Xe]6s24f9 6s24f9 4f9

titanium (Ti) ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s2 2s2 2p6 3s2 3p6 ↑↓ ↑ ↑ 4s2 3d2 1s22s22p63s23p64s23d2 [Ar]4s23d2 4s23d2 3d2

22. A chlorine atom in its ground state has a total of seven electrons in orbitals related to the atom’s third energy level. ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑ 1s2 2s2 2p6 3s2 3p5 How many of the seven electrons occupy p orbitals? 5 How many of the 17 electrons in a chlorine atom occupy p orbitals? 11

23. When a sulfur atom reacts with other atoms, electron s in orbitals related to the atom’s third energy level are involved. How many such electrons does a sulfur atom have? Sulfur (16 electrons) has the electron configuration [Ne]3s23p4. Therefore, 6 electrons are in orbitals related to the third energy level of the sulfur atom

24. An element has the ground-state electron configuration [Kr]5s24d105p1. It is part of some semiconductors and used in various alloys. What element is it? Indium (In)