Based on:
Bromine: [Ar] 3d10 4s2 4p5
Iodine: [Kr] 4d10 5s2 5p5
Chlorine: [Ne] 3s2 3p5
what are the chemical property similarities based on the electron configuration?
4p5, 5p5, 3p5 should tell you that all want to gain one electron to fill the outside shell. So all have an oxidation state of -1. If you will go to Google and type in chlorine, bromine, iodine,(individually) and scroll down on each to chemical properties, you will be able to write reactions for all that are essentially the same.
To determine the chemical property similarities based on the electron configuration, we need to compare the valence shell electron configuration of the elements - the outermost shell in the electronic structure.
Bromine: [Ar] 3d10 4s2 4p5
Iodine: [Kr] 4d10 5s2 5p5
Chlorine: [Ne] 3s2 3p5
From these electron configurations, we can see that all three elements - bromine, iodine, and chlorine - have five electrons in their outermost p-shell (not including any d or s electrons). This means that they all have the same number of valence electrons, specifically five.
Valence electrons play an essential role in determining the chemical properties of an element. Since these three elements have the same number of valence electrons, they exhibit similar chemical properties.
One of the significant chemical properties exhibited by elements with five valence electrons is their tendency to gain one electron to achieve a stable octet (eight valence electrons), as this will result in a more stable electron configuration. This means that all three elements can readily accept an additional electron to achieve stability. As a result, bromine, iodine, and chlorine tend to exhibit similar reactivity, especially when it comes to forming compounds through the sharing or transfer of electrons. They all belong to the halogen group on the periodic table and commonly form negative ions (anions) when reacting with other elements.
Therefore, based on their electron configurations, the chemical property similarity between bromine, iodine, and chlorine is their tendency to react and achieve a stable octet by gaining one electron.