Which subshell fills first

Answer: 2p is filled first. According to the holding capacity of different orbitals the sequence of filling the difference orbitals is, 1s 2s 2p 3s 3d and on and on…. To find this series Azimuthal quantum number helps……. If value of n is smaller then it will be filled first and also it less energy than upcoming orbitals. Therefore 3s has larger energy than 2p. Mortimer, C. Wadsworth Publishing Company, California Nelson, P. Petrucci, R.

Pearson Prentice Hall, Toronto Rleck, D. Sanderson, R. Silberberg, M. Higher Education, New York Scerri, E. Its Story and Its Significance. Oxford University Press, Oxford What is the periodic table? And what does quantum mechanics contribute to the question?

Schwarz, W. Quantum Chem. Toomey, R. Vanquickenborne, L. Viossat, V. Whitten, K. Cengage Learning, US Wang, S. Zumdahl, S. Download references. The authors thank the support of the Bu-Ali Sina University. Special thanks to Prof.

You can also search for this author in PubMed Google Scholar. Correspondence to Sadegh Salehzadeh. Reprints and Permissions. Salehzadeh, S. However, the 4s fills first in the 4th period, and are in the s-block of the periodic table. For first row transition metals its only more stable for chromium and copper to excite the 4s electron to the 3d subshell to give either a half filled or completely filled subshell.

No other first row neutral elements do this. When ionizing a transition metal an element in the d-block electrons will be pulled out of the s orbital before the d orbital. The exceptions are d5 and d