Question

Identify the symbol for the missing element in each period.

Cr

Mn

Co

Answer 1

• The atomic number of Chromium (Cr) is 24.
• Electrons per shell are 2, 8, 8, 6
• Number of shells = Period number.
• Number of shells = 4
• So, the elements belong to period 4.
• The elements belonging to Period 4 from Chromium are manganese, iron, and cobalt.
• Hence, the missing element is Iron (Fe).