How many electrons can be in each shell?
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.
The subshell has one orbital for a total of 2 electrons. The subshell has three orbitals for a total of 6 electrons. The subshell has five orbitals for a total of 10 electrons. The subshell has seven orbitals for a total of 14 electrons.
- The aufbau principle states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s shell is filled before the 2s subshell is occupied. Aufbau is a German noun that means construction or "building-up".
- Table of Allowed Quantum Numbers
n l Orbital Name 4 0 4s 1 4p 2 4d 3 4f
- This tells us that each subshell has double the electrons per orbital. The s subshell has 1 orbital that can hold up to 2 electrons, the p subshell has 3 orbitals that can hold up to 6 electrons, the d subshell has 5 orbitals that hold up to 10 electrons, and the f subshell has 7 orbitals with 14 electrons.
The s sublevel has just one orbital, so can contain 2 electrons max. The p sublevel has 3 orbitals, so can contain 6 electrons max. The d sublevel has 5 orbitals, so can contain 10 electrons max. And the 4 sublevel has 7 orbitals, so can contain 14 electrons max.
- According to the Aufbau principle, the 4s sublevel is filled before the 3d sublevel because the 4s is lower in energy. As the 3d sublevel becomes populated with electrons, the relative energies of the 4s and 3d fluctuate relative to one another and the 4s ends up higher in energy as the 3d sublevel fills.
- Method 1 Assigning Electrons Using a Periodic Table
- Find your atom's atomic number.
- Determine the charge of the atom.
- Memorize the basic list of orbitals.
- Understand electron configuration notation.
- Memorize the order of the orbitals.
- Fill in the orbitals according to the number of electrons in your atom.
- A sublevel is an energy level defined by quantum theory. In chemistry, sublevels refer to energies associated with electrons. In physics, sublevels may also refer to energies associated with the nucleus. Shell 5 can hold up to 50 electrons,
The fourth shell has 4 subshells: the subshell, which has 1 orbital with 2 electrons, the subshell, which has 3 orbitals with 6 electrons, the subshell, which has 5 orbitals with 10 electrons, and the subshell, which has 7 orbitals with 14 electrons, for a total of 16 orbitals and 32 electrons.
- The principal quantum number, (n), describes the energy of an electron and the most probable distance of the electron from the nucleus. In other words, it refers to the size of the orbital and the energy level an electron is placed in. The number of subshells, or (l), describes the shape of the orbital.
- The fourth shell has 4 subshells: the subshell, which has 1 orbital with 2 electrons, the subshell, which has 3 orbitals with 6 electrons, the subshell, which has 5 orbitals with 10 electrons, and the subshell, which has 7 orbitals with 14 electrons, for a total of 16 orbitals and 32 electrons.
- Discussion: Each of the 7 4f orbitals accommodates a pair of electrons. There are 14 elements in the lanthanides, the 4f block elements.
Updated: 25th September 2018