Question

The position of certain elements in the Modem Periodic Table is shown below. Using the above table answer the following questions giving reasons in each case: Out of $\mathrm{H},\mathrm{C},\mathrm{F}$ which has the largest atomic size?

Answer 1

Modern periodic table:

• “The physical and chemical properties of the elements are periodic functions of their atomic numbers”
• The horizontal rows are called periods while the vertical columns are known as groups.

Atomic size

• Generally, the atomic size increases on going down the group and decreases on going left to right in a period.

Largest atomic size

• Element F is argon.
• The symbol for argon is $\text{Ar}$
• The atomic number of argon is $18$.
• Argon has more number of protons, neutrons, and electrons compared to element H$\left(\mathrm{He}\right)$, and element C$\left(\mathrm{Ar}\right)$.
• So, element F has the largest atomic size.