What is the shielding effect, dealing with the electron vs. the nucleus?
http://en.wikipedia.org/wiki/Shielding_effect
thanks Dr. Bob
The shielding effect refers to the phenomenon where electrons in an atom shield or screen each other from the full attractive force of the nucleus. In other words, it refers to the reduction in the net positive charge felt by an electron in an atom due to the presence of other electrons.
To explain the shielding effect, we need to consider the electron configuration of an atom. Electrons occupy different energy levels or shells around the nucleus, with each shell having one or more subshells. The shells closer to the nucleus have lower energy levels and are filled with electrons first, following the Aufbau principle.
When an electron in an atom is shielded, it means that the electron is partially or fully shielded from the attractive force exerted by the positively charged nucleus. This is primarily due to the repulsion between electrons. The inner electrons, which occupy the lower energy levels, act as a shield or barrier that reduces the effective positive charge felt by the outer electrons.
The shielding effect can be explained by the concept of effective nuclear charge (Zeff). Zeff is the net positive charge felt by an electron in an atom after accounting for the shielding effect. It is calculated by subtracting the number of shielding electrons from the total number of protons in the nucleus.
To determine the shielding effect and Zeff, you would typically need to know the electron configuration of the atom you are studying. The electron configuration tells you how many electrons are present in each shell and subshell. By looking at the electron configuration, you can identify the number of shielding electrons for a particular electron.
It's important to note that the shielding effect is not the same for all electrons in an atom. Outer electrons experience less shielding compared to inner electrons since they are further away from the nucleus and are shielded by fewer electrons.
Overall, the shielding effect plays a crucial role in understanding various atomic properties, such as atomic size, ionization energy, and electron affinity. It helps explain the interactions between electrons and the nucleus within an atom.