Electrons, Energy Levels & Atomic Orbitals (Cambridge (CIE) AS Chemistry): Exam Questions

The model of the nuclear atom was first proposed by Ernest Rutherford. He developed this model on the basis of results obtained from an experiment using gold metal foil.

Complete the Table 2.1 with information for two of the particles in an atom of ¹⁹⁷Au.

Table 2.1

A sample of gold found in the earth consists of only one isotope.

i) Explain what is meant by the term isotopes

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ii) A different sample of gold contains more than one isotope.

Suggest why this different sample of gold has the same chemical properties as the sample found in the earth.

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Gold(III) chloride, traditionally called auric chloride, is one of the most common compounds of gold.

It has the formula AuCl₃.

Complete the electron configuration for the chloride ion using box notation.

On the axes shown in Fig. 2.1, draw a sketch diagram of one of each different type of orbital that is occupied by the electrons in a Period 3 element. 

Label each type of orbital. 

Fig. 2.1

State the full electron configuration for chromium.

State the meaning of [Ar] and complete the orbital diagram shown in Fig. 2.1 for chromium.

Fig. 2.1

This question is about the chromium(III) ion, .

i) State the number of protons, electrons, and neutrons in the chromium(III) ion. 

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ii) Write the full electron configuration for the chromium(III) ion. 

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Electron configurations give you a summary of where you can find an electron around the nucleus of an atom. They can also be determined for an ion after an atom loses or gains electrons.

i) State the full electron configuration of the rubidium ion, . 

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ii) State and explain the relative size of a rubidium ion compared to a krypton atom. 

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The electrons in an atom are found in orbitals around the nucleus, which have different energy levels sometimes called shells.

i) The fourth shell consists of the atomic orbitals 4d, 4f, 4p and 4s. List these orbitals in order of increasing energy. 

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ii) State the number of atomic orbitals present in 4d, 4f, 4p and 4s. 

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Rubidium forms an ionic compound with selenium, Rb₂Se Using boxes to represent orbitals and arrows to represent electrons, sketch the orbital diagram of the valence shell of selenium on the axis provided in Fig. 3.1.

Fig. 3.1

In the blast furnace, carbon can react with oxygen to form carbon dioxide and carbon monoxide.

Write one equation for the this reaction. 

Identify and draw the subshell on Fig. 5.2 which has the highest occupied energy level in an oxygen atom.

 Subshell ……………………………. 

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Diagram

Fig. 5.2

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i) Complete Fig. 5.2 to show the excited state of a carbon atom.

 Fig. 5.2  

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ii) Identify the type of hybridisation that arises in a molecule of carbon monoxide for both atoms and explain how this hybridisation occurs

Hybridisation ………….

Explanation

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