Which of the following property(ies) of all the alkali metals increase(s) with increase in their atomic number?
Which of the following property(ies) of all the alkali metals increase(s) with increase in their atomic number?
The correct options are
A Solubility of their hydroxides
B Thermal stability of their carbonates
C Softness
1) The solubility of their hydroxides increases with their
atomic number due to a decrease in lattice energy.
2) The thermal stability of carbonates increases with an increase in the atomic number. As the atomic number increases, charge density decreases and hence
it causes less distortion to the negative ion.
3) Softness increases with increasing atomic numbers as the
size of the metal increases and the electrons are not compactly arranged.
Moreover, the lattice energy also decreases, leading to an increase in softness.
4) Hydration energy depends on the size of the cation.
Smaller the size, higher the hydration energy. Hence with increasing atomic
number, hydration energy decreases.
Hence options A, B and C are correct.
A Solubility of their hydroxides
B Thermal stability of their carbonates
C Softness
1) The solubility of their hydroxides increases with their atomic number due to a decrease in lattice energy.
2) The thermal stability of carbonates increases with an increase in the atomic number. As the atomic number increases, charge density decreases and hence it causes less distortion to the negative ion.
3) Softness increases with increasing atomic numbers as the size of the metal increases and the electrons are not compactly arranged. Moreover, the lattice energy also decreases, leading to an increase in softness.
4) Hydration energy depends on the size of the cation. Smaller the size, higher the hydration energy. Hence with increasing atomic number, hydration energy decreases.
Hence options A, B and C are correct.
