Neco 2022 Chemistry Question 2

Practice essay / theory question 2 from the 2022 Neco Chemistry examination. This question covers periodic table, oxidation numbers, electron configuration, periodic trends, percentage composition .

Neco 2022 Chemistry Essay / Theory

Topics: periodic table oxidation numbers electron configuration periodic trends percentage composition

Question 2 NECO • 2022 • CHEMISTRY • essay

The diagram shows the structure of potassium chlorate, KClO₃, with a potassium ion (K⁺) and a chlorate ion (ClO₃⁻). The chlorine atom is central and is bonded to three oxygen atoms. Using the information from the diagram and the periodic table:

Question Parts

( a )

Assign the oxidation number of each element (K, Cl and O) in KClO₃.

( b )

Write the ground‑state electron configuration for each element present in the compound.

( c )

Among K, Cl and O, which element has the highest first ionisation energy? State the element and give a concise explanation based on periodic trends.

( d )

Calculate the mass percent of chlorine in pure KClO₃. (Atomic masses: K = 39.10 g mol⁻¹, Cl = 35.45 g mol⁻¹, O = 16.00 g mol⁻¹.) Give your answer to one decimal place.

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About This Question

This is Neco 2022 Chemistry Question 2. It is one of the essay questions from the 2022 Neco Chemistry examination.

The question covers periodic table, oxidation numbers, electron configuration, periodic trends, percentage composition .

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