Question

Which element does the electron configuration 1s22s22p2 represent? B C N K

Answer 1

Answer:

Carbon

Explanation:

the electronic configuration corresponds to the number of electrons that an atom of an element has and these are compensated with the number of protons in the nucleus of the element, therefore the number of protons in the nucleus is equal to the number of electrons in the orbitals.

The number of protons in the nucleus corresponds to the number Z, this is what allows us to differentiate between one element and another  

$1s^2 2s^22p^2$

We add the electrons

2+2+2=6

The number of electrons is 6 that matches the number of protons (which is the number Z)

We look for in the periodic table the element Z = 6 (atomic number)

The element that corresponds to this number is carbon

Answer 2

The electron configuration is 1s2 2s2 2p2, then the number of electrons is 2 + 2 + 2 = 6. The number of electrons equals the number of protons and this is the atomic number. So, the atomic number of the element is 6. In a periodic table you can find that the element with atomic number 6 is carbon. So the answer is C.