Quantum example sentences

When we move from lithium to fluorine across the second period, successive electrons are added to orbitals in the same principal quantum level and the shielding of the nuclear charge by the inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus.For alkali metals and halogens, as we descend the groups, the principal quantum number (n) increases and the valence electrons are farther from the nucleus.When we consider the same principal quantum level, an s-electron is attracted to the nucleus more than a p-electron.When we move from lithium to fluorine across the second period, successive electrons are added to orbitals in the same principal quantum level and the shielding of the nuclear charge by the inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus.In the preceding unit we have learnt that an electron in an atom is characterised by a set of four quantum numbers, and the principal quantum number (n ) defines the main energy level known as shell.This is because when an electron is added to O or F, the added electron goes to the smaller n = 2 quantum level and suffers significant repulsion from the other electrons present in this level.The period number corresponds to the highest principal quantum number (n) of the elements in the period.The seventh period is incomplete and like the sixth period would have a theoretical maximum (on the basis of quantum numbers) of 32 elements.For the n = 3 quantum level (S or Cl), the added electron occupies a larger region of space and the electron-electron repulsion is much less.It is then easy to visualize the significance of quantum numbers and electronic configureurations in periodicity of elements.Large positive electron gain enthalpies because the electron has to enter the next higher principal quantum level leading to a very unstable electronic configureuration.An element s location in the Periodic Table reflects the quantum numbers of the last orbital filled.When we consider the same principal quantum level, an s-electron is attracted to the nucleus more than a p-electron.