Question

Among the species \[B{r^ - }\], \[Br\] , \[B{r^ + }\] the smallest one in size is____
A.$B{r^ - }$
B.$Br$
C.$B{r^ + }$
D.None of these

Answer 1

Hint: We have to remember that the measure of the size of the chemical elements are termed as the atomic radii. Atomic radii is the distance from the center of the nucleus to the boundary of the surrounding shells or electrons. In the early twentieth century the chemists discovered the atomic radii.

Complete answer:
-We need to know that in an atom the electrons form clouds the shell of an atom. The atom contains a shell, if we add an electron to the atom the electron goes to the outermost shell. If we remove an electron from the atom that would become positive and if we add an electron to the atom that would become negative.
-Among \[B{r^ - }\] , \[Br\] , and \[B{r^ + }\] , the $B{r^ - }$ means an extra electron is in the outermost shell. $B{r^ + }$ means an electron is removed from the bromine atom.
-$Br$ means neither an electron is added nor the electron is removed.
-In $B{r^ + }$ ion, the positive charge attracts the valence shell electrons and pulls their electrons closer so the radius of the atom is decreased.
-In $B{r^ - }$ ions, the negative charge of the bromine atom will be repelled. If the repulsion is more the size of the atom is increased. So the force of attraction between the nucleus and all the electrons are reduced so the size of the atom is increased.
So, option C, $B{r^ + }$ is the correct answer.

Note:
We need to remember that whenever an electron is added to an atom, the atom becomes a negative ion and always cations are smaller in size than anions. The size of atom is,
Anions > Neutral atom > Cations.
We have to remember that in periodic tables, when we move across the period as left to right, the atomic size of the atom decreases whereas when we move down to the table, the atomic size of the element increases.