Chemistry 9701 · AS & A Level · Chemical energetics

Chemical energetics — practice question

(a)[1]

Complete the electronic configurations for the atoms below. fluorine: $1s^2\,\ldots$ sulfur: $1s^2\,\ldots$

(b(i))[1]

Write an equation that represents the thermal decomposition of $\text{HCl}$.

(b(ii))[1]

Using all relevant bond energy values from the Data Booklet, explain why the thermal stability of $\text{HF}$ is much greater than that of $\text{HCl}$.

(c)[2]

Explain what is meant by the term electronegativity, and how it relates to bond polarity.

(d(i))[2]

Draw a ‘dot-and-cross’ diagram to show the bonding in $\text{SF}_4$. Include all outer shell electrons in your diagram.

(d(ii))[1]

State whether a molecule of $\text{SF}_4$ has a dipole moment. Explain your answer.

(e)[1]

Suggest a reason why sulfur can form both $\text{SF}_4$ and $\text{SF}_6$ whereas oxygen can only form $\text{OF}_2$.

(f(i))[1]

State a major source of atmospheric sulfur dioxide.

(f(ii))[1]

State one environmental consequence of atmospheric sulfur dioxide.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct configurations: fluorine, $1s^22s^22p^5$, and sulfur, $1s^22s^22p^63s^23p^4$

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