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Periodic Classification of Elements — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10SciencePeriodic Classification of Elements3 Marks
Question
Write the electronic configuration of two elements X and Y whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element X reacts with element Y. Draw electron-dot structure of the product and also state the nature of the bond formed between both the elements.
✓

Answer

Atomic number of element $X=20$
Electronic configuration of element $X=2,8,8,2$
Atomic number of element $Y=17$
Electronic configuration of element $Y=2,8,7$
When $X$ reacts with $Y$, it loses the two valence electrons (valency 2). These two valence electrons are accepted by two $Y$ atoms (valency 1).
Hence, the molecular formula of the compound formed between $X$ and $Y$ is $X Y_2$.
Electron-dot structure:

Ionic bond is formed between the elements X and Y in compound $XY _2$.

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