Answer:
Step-by-step explanation:
The Lithium atom and Lithium cation have different electronic configurations. The Lithium atom has an electronic configuration of 1s² 2s², while the Lithium cation has an electronic configuration of 1s².
The Lithium cation is smaller than the Lithium atom due to a few reasons:
Fewer Energy Levels: The valence shell (outermost electron shell) of the Lithium atom has 2 energy levels, while the valence shell of the Lithium cation has only 1 energy level. This means that the distance between the valence electrons and the nucleus is smaller in the cation, making it smaller in size.
Less Shielding Effect: The shielding effect refers to the core electrons (inner electrons) that shield the valence electron from the pull of the nucleus. In the Lithium cation, there are no core electrons present, so the valence electrons are more strongly attracted to the protons in the nucleus. This stronger attraction pulls the electrons closer to the nucleus, resulting in a smaller size.
More Nuclear Charge: The Lithium atom has three protons and three electrons, creating a balanced attraction between them. However, when one electron is lost in the formation of the Lithium cation, the number of protons remains the same while the number of electrons decreases. This means that the positive charge from the protons becomes stronger relative to the remaining electrons, causing them to be pulled closer to the nucleus and resulting in a smaller size.