MC test: Electron configuration

Multiple choice test on 2.2 Electron configuration

Use the following 'quiz' to test your knowledge and understanding of this sub-topic. You will need access to a periodic table (Section 6 of the IB data booklet).

If you get an answer wrong, read through the explanation carefully to learn from your mistakes.

Which electronic transition occurs when a gaseous hydrogen atom in its ground state is ionized?

In its ground state the electron is in the n= 1 energy level and it is completely removed from the atom when it is ionized.

 

Which are used to explain and deduce the electron configuration of an element?

I. The aufbau principle

II. Hund's rule

III. Pauli exclusion principle

These three rules/principles are mentioned on the syllabus but do not need full explanations. Essentially Hund's rule states that electrons fill orbitals singly before pairing up and Pauli's exclusion principles limits the number of electrons in each orbital to two, each having opposite spins. The aufbau principle states that lower energy levels and sub-levels are filled first.

 

Which series of transitions occur to produce the discrete lines that occur in the visible region of the emission spectrum of hydrogen?

 

Lines are produced in the emission spectra when electrons emit photons as they fall from higher to lower energy levels. The visible region is due to electrons falling from higher levels to the n=2 level. 

 

The main energy levels occupied by electrons in an atom are designated by the letter n. What does n stand for?

Each electron is defined by four different quantum numbers. The principle quantum number n describes the main energy levels.

How many orbitals are present in the n = 3 main energy level?

There are three sub-levels, 3s, 3p and 3d. The s sub-level has 1 orbital, the p sub-level 3 orbitals and the d sub-level 5 orbitals giving a total of 9. 

 

What is the electron configuration of bromine?

Bromine (Z = 35) has 35 electrons. [Ar] has 18 electrons, two electrons in the 4s, ten in the 3d and the remaining five in the 4p sub-level.

 

Which is the correct orbital diagram (arrows in boxes) for a carbon atom?

Electrons pair up with opposite spins in full orbitals and occupy degenerate (equal energy) orbitals in the same sub-level singly first, all spinning the same way, before pairing up (Hund's rule).

 

What is the electron configuration of a copper atom?

Normally the 4s fills completely before the d sub-level fills but Cr and Cu are exceptions.

 

Which are correct statements about the 2px orbital?

I. It is orthogonal (at 90o) to the 2py and 2pz orbitals.

II. It is at the same energy level as the 2py and 2pz orbitals.

III. It has a 'dumbbell' shape lying along the x axis .

The three 2p orbitals are of equal energy lying along the three mutually orthogonal axes.

 

Which is the correct orbital diagram (arrows in boxes) for the 4s and 3d orbitals in the Fe3+ ion?

The electron configuration of Fe (Z = 26) is [Ar]4s23d6. When it loses 3 electrons to form Fe3+ it loses both 4s electrons and one of the 3d electrons so the electron configuration of Fe3+ is [Ar]3d5. The five d orbitals will each contain one electron, all of them spinning in the same direction according to Hund's rule.

 

Total Score:
All materials on this website are for the exclusive use of teachers and students at subscribing schools for the period of their subscription. Any unauthorised copying or posting of materials on other websites is an infringement of our copyright and could result in your account being blocked and legal action being taken against you.