Share

# The Atomic Number of an Element is 20. in Modern Periodic Table, this Element is Placed: (A) 2nd Period (B) 4th Period (C) 3rd Period (D) 1st Period - Science

Course

#### Question

The atomic number of an element is 20. In modern periodic table, this element is placed:

(a) 2nd period
(b) 4th period
(c) 3rd period
(d) 1st period

#### Solution

(b) 4th period.

Electronic configuration : K L M N
2 8  8  2
Hence, from the electronic configuration, it is clear that the outermost electron goes into the 4th shell. So, the element would be placed in the 4th period.

Is there an error in this question or solution?