Electronegativity

[Jasmeen Kaur 2D]

In regards to NaI and NaF, NaI is more covalent in character than NaF and thus NaF is more soluble in water. So why is BaO more soluble in water than MgO even though BaO is more polarizable and covalent in character than MgO?? Am I getting two different concepts confused? I thought if a compound is more covalent in character is it harder to dissolve?

[305961049]

Hey! Hope this helps.

For NaI and NaF: NaI is more covalent due to the larger and more polarizable Iodine atom. However, NaF is more soluble in water. This is because the size of ions matters, and smaller ions in NaF result in stronger ionic bonds, making it less soluble.

In terms of BaO and MgO: BaO is more soluble in water than MgO. Despite BaO having more covalent character due to larger ions, the size of ions becomes crucial. The larger Ba²⁺ and O²⁻ ions in BaO lead to weaker electrostatic forces, making BaO more soluble than MgO. Size often outweighs covalent character in determining solubility in simple ionic compounds. While BaO may have more covalent character due to the larger, more polarizable ions, the effect of size on solubility often outweighs this covalent character in simple ionic compounds. Larger ions can disrupt the crystal lattice more effectively, leading to higher solubility.

[Jasmeen Kaur 2D]

Why doesn't the reasoning for BaO and MgO apply to NaI and NaF even though Iodine is larger that F?

[305961049]

The reasoning for the solubility differences between NaI and NaF compared to BaO and MgO lies in the nature of the ions and the specific characteristics of the compounds. In NaI, the iodine ion (I⁻) is larger and more polarizable than the fluorine ion (F⁻). The larger size and higher polarizability of iodine favor covalent character in the Na-I bond. In NaF, the smaller fluorine ion results in a more ionic character in the Na-F bond.

The size difference in the ions is significant, leading to different bonding characteristics. The larger, more polarizable iodine ion promotes a more covalent character in NaI, whereas the smaller fluorine ion promotes a more ionic character in NaF.

In BaO, the barium ion (Ba²⁺) is larger than the magnesium ion (Mg²⁺). Both ions are highly charged, but the size difference is more pronounced in this case. In MgO, the smaller size of the magnesium ion results in stronger electrostatic forces in the ionic bond. The key difference here is that both ions are positively charged, and the larger size of the barium ion leads to weaker electrostatic forces compared to the smaller magnesium ion.

In NaI and NaF, the difference in size and polarizability between iodine and fluorine ions leads to different bonding characteristics. In BaO and MgO, both ions are positively charged, but the significant size difference between barium and magnesium ions results in different solubility behavior. The specific characteristics of the ions in each compound play a crucial role in determining the type and strength of the chemical bonds formed, which, in turn, influence solubility in water.

Sorry this was late and I hope this helps!