The valency of Bromine (Br) is one.
Bromine, a member of the halogen group (Group 17) of the periodic table, consistently exhibits a valency of one in most of its compounds. This characteristic valency is directly related to its electronic configuration and its tendency to achieve a stable octet.
Understanding Bromine's Valency
Bromine atoms possess seven valence electrons. To attain a stable electron configuration, similar to that of a noble gas (which has eight valence electrons, an octet), a bromine atom readily accepts or shares one additional electron.
- Electron Configuration: Bromine's electron configuration ends in
...4s²4p⁵, indicating seven electrons in its outermost shell. - Octet Rule: According to the octet rule, atoms tend to gain, lose, or share electrons to achieve a stable configuration with eight valence electrons.
- Valency Definition: Valency represents the combining capacity of an element, typically measured by the number of bonds an atom can form or the number of electrons it needs to gain or lose to achieve stability. Since bromine needs to gain just one electron to complete its octet, its valency is one.
This strong tendency to gain one electron makes bromine a highly reactive non-metal. It often forms ionic bonds with metals by gaining an electron (forming a Br⁻ ion) or covalent bonds with non-metals by sharing one electron.
Key Properties of Bromine Related to Valency
| Property | Value | Relevance to Valency |
|---|---|---|
| Atomic Number (Z) | 35 | Defines the number of protons and electrons. |
| Valence Electrons | 7 | Directly determines its combining capacity (valency). |
| Common Oxidation State | -1 | Reflects its tendency to gain one electron. |
| Group | 17 (Halogens) | All halogens typically exhibit a valency of one. |
| Tendency | To gain one electron to achieve a stable octet. | This specific action defines its valency as one. |
| Reactivity | High | Due to its strong desire to complete its octet with one electron. |
Examples of Bromine Compounds with Valency One
Bromine's valency of one is evident in numerous compounds:
- Hydrogen Bromide (HBr): Bromine shares one electron with hydrogen.
- Sodium Bromide (NaBr): Bromine gains one electron from sodium to form an ionic bond.
- Potassium Bromide (KBr): Similar to sodium bromide, bromine accepts one electron from potassium.
- Methyl Bromide (CH₃Br): Bromine forms a single covalent bond with a carbon atom.
In these common compounds, bromine consistently forms a single bond or accepts a single electron, reinforcing its valency of one. For further information on valency and halogens, you can refer to resources on chemical valency and halogen elements.
