2A 3 ATOMIC ORBITALS AND ELECTRON CONFIGURATIONS

What is a quantum shell?

1. It is the particular energy level at which some electrons exist.

The electrons on the first quantum shell have the highest energy level, true or false.

1. False, in fact the opposite.

Does the first quantum shell have a sub shell?

1. yes

List the subshells in the first quantum shell.

1. 1s subshell.

List the subshells in the second quantum level.

1. 2s,2p,2d

List the subshells in the 3rd quantum shell.

1. 3s, 3p, 3d

List the subshells in the 4th quantum level.

1. 4s, 4p, 4d, 4f

List the energy level from lowest to highest in the subshells.

1. s, p, d, f

What is an orbital?

1. It is the 3-dimensional area which the electron is likely to be found.

What shape is the s orbital?

1. It is a sphere.

What shape is the p orbital?

1. Elongated dumbbell shape

How many p orbitals are present?

1. 3 separate p orbitals, along the x, y, z axis.

How many d orbitals are present in the d sub-shell?

1. 5

How many electrons stored in each orbital?

1. 2

Number of electrons in s sub-shell?

1. 2

Number of electrons in p subshell.

1. 6

Number of electrons in d subshell.

1. 10

Number of electrons in f subshell.

1. 14

Number of electrons in 1st quantum shell.

1. 2

Number of electrons in 2nd quantum shell.

1. 8

Number of electrons in 3rd quantum shell.

1. 18

Number of electrons in 4th quantum shell.

1. 32

What is the general rule of thumb for electrons filling orbitals?

1. The lowest energy orbitals get filled first.

Explain why the electronic configuration of Potassium is different to what we expect?

1. Potassium’s electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s1.

2. This is because the exact energies of the electrons in the orbitals are determined by the number of protons (proton number, attractive force exerted from the nucleus) in the nucleus of the atom and the repulsion between all of the electrons present in the atom (Electron-electron repulsion).

3. For both calcium and potassium atoms, the energy is the 4s orbital is lower than that of the 3d orbitals.

What is the electronic configuration of calcium?

1. 1s2 2s2 2p6 3s2 3p6 4s2

Name the orbitals from inner to most outer.

1. 1s 2s 2p 3p 3s 3p 3d 4s 4p

What should we note about the energy of 4s orbitals in the elements after calcium?

1. The orbital 3d has less energy than the 4s orbitals, in all of the elements after calcium.

2. Potassium and calcium are exceptions.

Although the 3d orbital gets filled with electrons before the 4s orbital, why are two electrons pushed to the 4s orbital instead of them filling the 3d orbital?

1. 3d orbitals are more compact than 4s orbitals, as a result the electrons experience more electron-electron repulsion.

What is the Aufbau principle?

1. It is the general rule that as protons are added to the nucleus of the atom, electrons are added to the orbitals of increasing energy.

What is Hund’s rule?

1. Hund’s rule states that the electrons will occupy the orbitals singly before pairing takes place.

What is the Pauli exclusion Principle?

1. Pauli Exclusion Principle states that two electrons cannot occupy the same orbital unless they have opposite spins.

Suggest why the electron in 2py orbital is not located in the 2px orbital?

1. Two electrons in a single orbital would increase the electron-electron repulsion and the orbital energies of the electrons.

2. The preferred electron configuration is the one of the lowest energy.