University of Portsmouth named the UK's most affordable city for students in the Natwest Student Living Index 2016. On Friday 4 May 2018, the University of Portsmouth was revealed as the main shirt sponsor of Portsmouth F.C. for the 2018-19, 2019-20 and 2020-21 seasons. The history of the university dates to 1908, when the Park building opened as a Municipal college and public library. The focus was on chemistry and engineering. The roots of the University can be traced back even further to the Portsmouth and Gosport School of Science and the Arts. Shortly after in the year of 1911 a Student Union
Effective atomic number interactions. For instance, lithium, atomic number 3, has two electrons in the 1s shell and one in the 2s shell. Because the two 1s electrons screen the protons to give an effective atomic number for the 2s electron close to 1, we can treat this 2s valence electron with a hydrogenic model. Mathematically, the effective atomic number Z can be calculated using methods known as "self-consistent field" calculations, but in simplified situations is just taken as the atomic number minus the number of electrons between the nucleus and the electron being considered. An alternative definition of the effective atomic number