Chapter U1.24, Problem 7E

Interpretation Introduction

Interpretation:

Outermost subshell for bromine, Br is to be named.

Concept introduction:

A periodic table can be divided into four zones, s block, p block, d block and f block. The element belonging to a particular block has the outermost electron in that particular subshell. For example in case of s block elements, the outermost electrons will occupy s subshell. Elements in p block will have its outermost electrons in p subshell.

Answer to Problem 7E

Outermost subshell for bromine, Br is ‘4p’.

Explanation of Solution

Given information:

Bromine has an atomic number of 35.

The atomic number of bromine is 35. It is located in p block of periodic table. Its position is in group 17 and period 4. In a neutral atom of bromine there are 35 electrons which are located in shells, n = 1, n=2, n=3 and n=4.

The electronic configuration of bromine is 1s² 2s² 2p⁶3s² 3p⁶ 3d¹⁰4s²4p⁵

It has 7 valence electrons which are located in fourth shell; that is in n = 4.

It has 4s and 4p subshells with 2 and 5 electrons respectively. Hence the outermost subshell of bromine is 4p.

Conclusion

By knowing the position of an element on a periodic table, one can predict the arrangement of electrons. The periodic table provides the information needed to write the electronic configurations.