Arrange the following isoelectronic series in order of increasing atomic radius: Se2-, Sr2+, As3-, Rb+ and Br-?

thank you

Sr2+, Rb+, Br-, Se2-, As3-

Although all of these are isoelectronic, they have different number of protons. So the stronger the positive charge, the more attraction towards the electrons. Sr has the most protons and As has the least. Therefore, Sr2+ is the smallest while As3- is the largest.

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Sr2+,Rb+,Br,Se2−,As3− Mastering chemistry ^_^