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💡 Same-element partners
When two atoms of the same element team up — hydrogen with hydrogen, oxygen with oxygen — they form a molecule of that element.
How does a hydrogen molecule form?
- Hydrogen (atomic number 1) has 1 electron in the K-shell.
- The K-shell needs 2 electrons to be full, so hydrogen needs one more.
- Two hydrogen atoms share one electron each → a shared pair → H₂.
- They are joined by a single bond , shown as H—H.
How does an oxygen molecule form (double bond)?
- Oxygen (atomic number 8) has 6 valence electrons; it needs 2 more.
- Two oxygen atoms share two electrons each — two shared pairs.
- This is a double bond , shown as O=O.
NCERT Question 2 — An element X has six
An element X has six electrons in its outer shell and forms a diatomic molecule. (i) Why would that be so? (ii) What kind of bond would it form? (iii) Draw the structure of the molecule it would form. (iv) A certain other element Y has two electrons in its second shell. Draw the structure of the molecule that X would form with Y.
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🤝 Together we are strong…
- Atoms share electrons to form covalent bonds.
- We too can share and care with people around us.
- Sharing builds strong relationships.
- It brings unity and stability.
- That is the foundation of a stronger community and nation.
⏸▶ Pause and Ponder
- 8. Nitrogen has five valence electrons. Draw the structure of the nitrogen molecule (N₂). → Each N needs 3 more electrons for an octet. Two N atoms share three pairs → a triple bond , written N≡N.
- 9. The atomic number of fluorine is 9. Explain the formation of the fluorine molecule (F₂). → F is 2, 7 — it needs 1 electron. Two F atoms share one pair → a single covalent bond , written F—F.
Important Definitions
- Molecule of an element — a molecule made of two or more atoms of the same element, e.g. H₂, O₂.
