Chemistry
State why water has two lone pairs of electrons in it's covalent molecule while ammonia has one lone pair.
Answer
Water contains two hydrogen atoms and one oxygen atom. The hydrogen atom [1] has one electron in it's valence shell while the oxygen atom [2,6] has 6 electrons in it's valence shell. Two hydrogen atom share one electron each and two unshared pairs of electrons are left as lone pairs as shown in the diagram below :
In the case of ammonia, it contains three hydrogen atoms and one nitrogen atom. Nitrogen atom [2,5] has five valence electrons and hydrogen atom [1] has one valence electron. In ammonia, each of the three hydrogen atoms are bonded to the nitrogen atom by a pair of shared electrons. Thus, the nitrogen atom in ammonia is left with one lone pair of electrons as shown in the diagram below:
Related Questions
An element 'X' has same number of electrons in its first & in its outermost shell. The electronic configuration of X2+ is :
- 2, 8, 1
- 2, 8
- 2, 8, 2
- 2, 8, 8
An element 'A' needs 4 electrons to attain stable electronic configuration of the nearest noble gas — Neon. An element 'B' needs 1 electron to attain stable electronic configuration of the nearest noble gas — Argon.
The covalent compound formed between A & B is :- AB3
- A4B
- A2B4
- AB4
Name the following:
- An electrovalent compound formed by transfer of one electron from a metallic atom to a non-metallic atom.
- A covalent hydrocarbon molecule, having four single covalent bonds.
- A covalent molecule, having two lone pair of electrons.
- A covalent molecule having a triple covalent bond.
- A covalent molecule having two shared pairs of electrons in it's molecule.
Give reasons for the following :
To attain stable electronic configuration of the nearest noble gas —
- Hydrogen atom 11H — needs one electron.
- Oxygen atom 168O — needs two electrons.
- Nitrogen atom 147N — needs three electrons.
- Carbon atom 126C — needs four electrons.
- Chlorine atom 3517Cl — needs one electron.