Question

How can I write the formula for potassium bromide?

Answer 1

Hint: As we know that potassium belongs to group 1 of the periodic table and it loses an electron to become a cation, and bromine belongs to group 17 of the periodic table and it gains an electron to become an anion. And we can write the formula of potassium bromide on the basis of this, which is a balanced oxidation state.

Complete answer:
- As we know that oxidation states basically indicate the hypothetical charge on the atom that is given on the basis of gain of electrons or loss of electrons to form a chemical bond.
- It is found that the oxidation number of an atom is equal to the total number of electrons that is added to the element or is removed from an element to reach the present state.
- As we know that potassium bromide is ionic in nature and we can write it in dissociated as well as in balanced form as: ${{K}^{+}}$ and $B{{r}^{-}}$ .
- It is found that ionic bonds are formed when the charges between non-metal anion and metal cation are equal and opposite. We can say that one ${{K}^{+}}$ cation will balance with one $B{{r}^{-}}$ anion, and cancel each other.
- Therefore, on the basis of this information we can write the formula for potassium bromide as KBr, based on their oxidation states.
- Hence, we can conclude that we can write the formula for potassium bromide as KBr.

Note:
- We should note that while writing the chemical formula we must know in which form the atom exists whether di, mono or triatomic, and we must also know the oxidation states. All these facts will help us to get the correct answer.