Question

An atom has electronic configuration of $2,8,18,7$

To which of the following element is chemically similar .
${}_7\text{N}{,}_{17}\text{Cl}{,}_{15}\text{P}$ and ${}_{18}\text{Ar}$

• A. ${}_{15}\text{P}$
• B. ${}_7\text{N}$
• C. ${}_{17}\text{Cl}$
• D. ${}_{18}\text{Ar}$

Answer 1

Answer: (C)

${}_{17}\text{Cl}$

The electronic configuration of an atom is $KLMN28187$
Atomic number of this atom is $35=(2+8+18+7)$
This atom would be chemically simillar to ${}_{17}\text{Cl}$ as both have seven electrons in this outermost shell.