Topic Details (Notes format)

Periodic Table History

Subject: Chemistry

Book: General Chemistry

The periodic table evolved from attempts to classify elements based on their atomic masses and properties. Dmitri Mendeleev’s 1869 arrangement left gaps for undiscovered elements, predicting their properties with remarkable accuracy. Later, Henry Moseley’s work on atomic numbers refined the table’s order. The periodic table remains central to chemistry, guiding research in discovering new elements and understanding chemical trends.

Practice Questions

What is the chemical formula for potassium nitrate?

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Which element is essential for the formation of hemoglobin?

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Which gas is used in neon signs?

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Which element is represented by the symbol 'Pb'?

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Which element is represented by the symbol 'Ag'?

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Which element has the atomic number 26?

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Which non-metal element is liquid at room temperature?

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Which gas is most abundant in Earth's atmosphere?

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