question_answer

                The atomic number of elements P, Q and R are 7, 11, 15 respectively. State with a reason which two elements are likely to have same chemical properties?

Answer:

\[P(Z=7\text{ })2,\text{ }5\] \[Q(Z=11)\text{ }2,\text{ }8,\text{ }1\] \[R(Z=15)\text{ }2,\text{ }8,\text{ }5\] From the above configurations it is clear that P and R have same number of electrons in their outermost shell and hence their valencies are same. Therefore they are likely to have same chemical properties.