Chapter 18, Problem 2STP

To determine

Number of electrons in the outer energy level of a chemically stable atom or element.

Answer to Problem 2STP

The correct option is (D).

Explanation of Solution

Calculation:

There are 2 elements in period 1 in the periodic table such as Hydrogen and helium. These can accommodate a maximum of 2 electrons in their outermost shell. Rest the entire element in the periodic table, either gain or lose the electrons to complete their octet.

All the other elements in the same table can have a maximum of 8 electrons in their outermost shell. They try to form compounds with other elements either by gaining or losing or sharing electrons. Every element tries to attain stability by completing its outermost shell.

Since the atom is stable, so it has 8 electrons in its outermost shell.

Therefore, options (A), (B), and (C) are wrong and option (D) is correct.

Conclusion:

Hence, a stable element will have 8 outermost electrons.