Sub-shells, orbitals & electron configuration

Oxygen has the electron configuration 1s²2s²2p⁴.

How are the electrons in an atom of oxygen arranged in the p-orbitals?

Your answer

This question is about transition elements.

Suggest the formulae of A, B and C.

Complex ion A:........

Solid B:........

Complex ion C:........

Cobalt (III) forms an octahedral complex ion D, which contains both ammonia and chloride ligands.

Complex ion D has a molar mass of 197.9 g mol^–1.

Determine the formula and charge of complex ion D.

Red blood cells contain haemoglobin which transports oxygen around the body.

For efficient transportation of oxygen, healthy human blood must be maintained at a pH value between 7.35 and 7.45.

Human blood acts as a buffer due to the presence of carbonic acid, H₂CO₃, and hydrogencarbonate, HCO₃^–, ions as shown below.

• Explain, using ligand substitution, how haemoglobin transports oxygen around the body.

• Determine whether a sample of blood with a [HCO₃^–]: [H₂CO₃] ratio of 8.5:1 is healthy.

Which ion(s) contain(s) one or more unpaired electrons?

1 Mn³⁺

2 V³⁺

3 Cu +

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer

This question is about magnesium and magnesium halides.

Magnesium has metallic bonding and is a good conductor of electricity.

Describe, with the aid of a labelled diagram, the metallic bonding in magnesium and explain why magnesium conducts electricity.

Include the correct charges on the particles in your diagram.

The 12 successive ionisation energies of magnesium are shown in Table 16.1.

Write an equation to represent the fourth ionisation energy of magnesium.

Include state symbols.

Explain how the successive ionisation energies provide evidence that magnesium is in Group 2 of the periodic table.

Electrons occupy orbitals.

In Table 16.2 below, add a tick (✓) below the ionisation numbers that are responsible for removing an electron from a full orbital in a magnesium atom.

The enthalpy change of solution for magnesium fluoride, MgF₂, can be determined indirectly using an energy cycle based on the enthalpy changes below.

Explain what is meant by enthalpy change of solution.

Calculate the enthalpy change of solution of MgF₂.

enthalpy change of solution =........ kJ mol^–1

In the diagrams below, each box represents an orbital and each electron is shown as an arrow.

Which diagram shows the correct arrangement of electrons in an atom of carbon?

Your answer

Select an element from the first three periods that fits each of the following descriptions.

The element that forms a 1– ion with the same electron configuration as helium.

The element with the highest first ionisation energy.

The element in Period 3 which has the successive ionisation energies shown below.

The element which forms a compound with fluorine that has octahedral molecules.

An element which reacts with water to form an acidic solution.

The element X, which forms a compound with hydrogen, XH₃, with a molar mass of 34.0 g mol^–1.

An element which forms a compound with hydrogen in which the element has an oxidation number of –4.

The element which has a density of 1.33 × 10^–3 g cm^–3 at room temperature and pressure.

Table 1.1 shows some properties of Period 3 chlorides.

Explain the properties shown in Table 1.1 in terms of bonding and structure.