Question

Identify the symbol for the missing element in each period.

Ge

As

Se

Answer 1

Step 1: Find the period number.

• The number of shells = period number.
• According to the question, all the elements represented belong to the same period.

Step 2: Finding the period number for one element $\left(\mathrm{Ge}\right)$:

Germanium $\left(\mathrm{Ge}\right)$

• The atomic number is $32$
• Electrons per shell $=2,8,8,14$
• Number of shells $=4$
• So, the elements belong to the period $4$
• The elements belonging to period $4$ are Germanium$\left(\mathrm{Ge}\right)$, Arsenic $\left(\mathrm{As}\right)$, Selenium (Se), Bromine $\left(\mathrm{Br}\right)$, and Krypton $\left(\mathrm{Kr}\right)$.

Hence, the missing element is Bromine $\left(\mathrm{Br}\right)$.