Formal Charges
Formal charges have an important role in organic chemistry since this concept helps us to know whether an atom in a molecule is neutral/bears a positive or negative charge. Even if some molecules are neutral, the atoms within that molecule need not be neutral atoms.
Polarity Of Water
In simple chemical terms, polarity refers to the separation of charges in a chemical species leading into formation of two polar ends which are positively charged end and negatively charged end. Polarity in any molecule occurs due to the differences in the electronegativities of the bonded atoms. Water, as we all know has two hydrogen atoms bonded to an oxygen atom. As oxygen is more electronegative than hydrogen thus, there exists polarity in the bonds which is why water is known as a polar solvent.
Valence Bond Theory Vbt
Valence bond theory (VBT) in simple terms explains how individual atomic orbitals with an unpaired electron each, come close to each other and overlap to form a molecular orbital giving a covalent bond. It gives a quantum mechanical approach to the formation of covalent bonds with the help of wavefunctions using attractive and repulsive energies when two atoms are brought from infinity to their internuclear distance.
![**Question:**
Which species below has the lowest number of valence electrons in its Lewis symbol?
- ○ Ar⁺
- ○ F⁻
- ○ Ga⁺
- ○ Mg²⁺
- ○ S²⁻
**Explanation:**
To solve this question, we need to understand what each species represents and how many valence electrons they have when considering their Lewis symbols:
1. **Ar⁺ (Argon ion)**: Argon is a noble gas with 8 valence electrons, but losing one electron results in Ar⁺ with 7 valence electrons.
2. **F⁻ (Fluoride ion)**: Fluorine has 7 valence electrons, and gaining one electron gives F⁻ 8 valence electrons.
3. **Ga⁺ (Gallium ion)**: Gallium has 3 valence electrons, and losing one electron results in Ga⁺ with 2 valence electrons.
4. **Mg²⁺ (Magnesium ion)**: Magnesium has 2 valence electrons, and losing both results in Mg²⁺ with 0 valence electrons.
5. **S²⁻ (Sulfide ion)**: Sulfur has 6 valence electrons, and gaining two electrons results in S²⁻ with 8 valence electrons.
The species with the lowest number of valence electrons in its Lewis symbol is **Mg²⁺** with 0 valence electrons.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F2b904a91-3e89-4710-bf14-7b4b1c7d4c29%2F54630a7a-a343-492e-8c23-53a5c3b12428%2F6pknsxv_processed.jpeg&w=3840&q=75)
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