Pauli exclusion principal says no two electrons can have same set of quantum number since for our distant universe three such electrons exist hence the correct answer for this is 3.
since we have 3 spin quantum number the configuration will be 1s3 2s3 2p2.
A noble gas has all orbital filled, first noble gas will have configuration 1s3 2s3 2p6 which means that its atomic number is 3+3+6 = 12
Calcium Nitrate is made up of three different elements and contains a total of nine atoms. This compound's formula is Ca(NO3)2. There is one calcium atom, two nitrogen atoms, and there are six oxygen atoms in calcium nitrate
D sublevel because the s sublevel has one orbital, the p sublevel has three orbitals, the d sublevel has five orbitals, and the f sublevel has seven orbitals. In the first period, only the 1s sublevel is being filled.