Question

23 ccc patterns what element has an electron configuration of 1s²2s²2p⁶3s²3p⁶4s² and which block is it in? use the periodic table.

Explanation:

Step1: Calculate number of electrons

Sum the electrons in each sub - shell. $2 + 2+6 + 2+6+2=20$.

Step2: Identify the element

The atomic number is equal to the number of electrons in a neutral atom. The element with atomic number 20 is calcium (Ca).

Step3: Determine the block

The last electron enters the s - subshell. Elements with the last electron in the s - subshell are in the s - block.

Answer:

The element is calcium (Ca) and it is in the s - block.