Question

Q.3. Select the correct option.
A student was asked to select two elements in a periodic table. He selects neon and
argon. In both these elements, the number of electrons in the outermost shell is_
(A) 2, (B) 6, (C) 7, (D) 8
Four students note down the names of the two metals from period 3.
Rita: Sodium and silicon
Nilesh: Magnesium and aluminium
Rohan: Sodium and Potassium
Preeti: Sodium and aluminium
​

Answer 1

For first part answer is

option D 8 electrons

for second part

Nilesh is the correct option

Explanation:

since argon and neon are inert gases which do not react with other substances so they have complete octet nd have 8 electrons in their outermost shell.

Answer 2

Answer:

• The number of electrons in the outermost shell of Neon and Argon is equal to eight. Therefore, the option (D) is correct.
• Nilesh and Preeti note down the correct names of the two metals from period 3.

Explanation:

• Nobles gases are the element of group 18. they have completely filled outermost shell. the general electronic configuration of noble gases is ns²np⁶. Therefore, they have eight electrons in their outermost shell. Neon and argon both are noble gases. Therefore,  the number of electrons in the outermost shell of Ne and Ar is 8.
• The elements of period 3 of periodic table are Sodium, Magnesium,  Aluminium, Silicon, Phosphorous, Sulphur, Chlorine and Argon. Sodium, Magnesium and Aluminium are metals while rest are non metals.
• Sodium is a alkali metal and magnesium is alkaline earth metal. Therefore, both Nilesh and Preeti write correct elements.
• Rita have written Silicon which belongs to period 3 but a non metal. Rohan have written Potassium which is metal but belongs to period 4.