Question

"1s² 2s² 2p⁶ is the electron configuration of which element?"

Select one:
a) Helium
b) Oxygen
c) Neon
d) Sodium

Answer 1

The electron configuration 1s² 2s² 2p¶ corresponds to the noble gas neon (Ne), which has a complete first and second energy levels, not to be confused with sodium (Na) which has an additional electron.

Step-by-step explanation:

The electron configuration 1s² 2s² 2p¶ represents the element neon (Ne). Each electron shell is denoted by a number and the letter represents the type of orbital (s or p). The superscript indicates the number of electrons in that orbital. Neon has a total of 10 electrons: 2 in the 1s orbital, 2 in the 2s orbital, and 6 in the 2p orbitals, which completely fills its first and second energy levels, making it a noble gas with a stable configuration.


This configuration does not include a 3s orbital, which is characteristic of sodium (Na), the alkali metal with an atomic number of 11 that has one more electron than neon, leading to the configuration 1s² 2s² 2p¶ 3s¹. Thus, the correct answer is c) Neon.