NOTE: valence configuration of B, Al, and Ga is ns2 np1 QUESTION: Which of the following has no electron in its valence p subshell? A. Ga, B. Al, C. B, D. Mn Ga 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1 Al 1s2 2s2 2p6 3s2 3p1 B 1s2 2s2 2p1 Mn 1s2 2s2 2p6 3s2 3p6 4s2 3d5 NOTE: valence configuration of B, Al, and Ga is ns2 np1 SCRIPT: Which of the following has no electron in its valence p subshell? Gallium… aluminum… boron… or manganese PAUSE CLICK To answer this question, let’s write the ground state electron configuration for these atoms. For Gallium, it’s 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1 For aluminum, the electron configuration, 1s2 2s2 2p6 3s2 3p1 For boron, the electron configuration is 1s2 2s2 2p1 And for manganese, it’s 1s2 2s2 2p6 3s2 3p6 4s2 3d5 The term valence refers to the outermost shell. So the valence shell of Gallium is the fourth shell. It has 2 electrons in the 4s subshell and one electron in the 4p subshell. HIGHLIGHT 4s2 and 4p1 For aluminum the valence shell is the third shell. It has 2 electrons in the 3s subshell and one electron in the 3p subshell. HIGHLIGHT 3s2 and 3p1 For boron, the valence shell is the second shell. It has two electrons in the 2s subshell and one electron in the 2p subshell. HIGHLIGHT 2s2 and 2p1 For manganese, the valence shell is the fourth shell. It has two electrons in the 4s subshell. The 4p subshell has no electron. The correct answer is D…. Manganese. You will notice that the valence configurations of Boron, aluminum and gallium all have two electrons in the valence s subshell and one electron in the valence p subshell. We say that the valence configurations of these atoms are the same: ns2 np1 Where n is the principal quantum number for the valence shell. HIGHLIGHT ns2 np1 This is generally true for atoms belong to the same column in the periodic table. Boron, Aluminum, Gallium, and the other elements in group three A, or column 13, all have one electron in their valence p subshell. Their valence p subshell configuration is pee one. Group four A, or column 14 … carbon silicon, germanium, tin, and lead have a valence p subshell configuration of p2 For atoms in Group five A or column 15, it’s p3 For atoms in group six A or column 16, it’s p4 For atoms in group seven A, or column 17, it’s p5. And for atoms in group eight A, or column 18, it’s p5…. Except for helium. These are the only elements with electrons in the valence p subshell. All of these elements are said to belong the the p block Their valence configurations are all of the type ns2 npx, Where n is the period or horizontal row where the element belongs And x is 1 for column 13, 2 for column 14, 3 for column 15, 4 for column 16, 5 for column 17, and 6 for column 18. CLICK PAUSE END RECORDING

p block 6 columns (13 to 18) (IIIA to VIIIA) ns2 npx

Video ID: 2-5-3 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08