Because bond lenth of a covalent bond is the distance between the nuclei of two bonded atoms.
Melting Point
As the size of alkali metals increases down the group the M-H bond becomes weaker hence its stability decreases from LiH to CsH
As you move down the group of alkali metals in the periodic table, the hardness of the metals generally decreases. This is due to the increasing atomic size and the weakening of metallic bonds, which makes the metals softer. For example, lithium is the hardest, while cesium is significantly softer. The increase in atomic radius results in less effective overlap of electron orbitals, contributing to the softer nature of the heavier alkali metals.
Down the group the size of atom increases. Hence the force of attraction between the nucleus and the electrons of the next atom decreases. Or in other words, the electronegativity decreases down the group.
The first. Going down metallicity decreases.
As we move down a group, electronegativity decreases.
Yes, the hardness of ice increases as the temperature decreases.
Hydration energy decreases down the group in the periodic table because the size of the ions increases as you move down a group. When ions are larger, they are less strongly attracted to water molecules. Therefore, larger ions exhibit lower hydration energies compared to smaller ions.
Melting Point
because down the group the cation becomes gets larger so the hydration energy decreases. so the solubility decreases
It increases
Atomic radius
As the size of alkali metals increases down the group the M-H bond becomes weaker hence its stability decreases from LiH to CsH
As you move down the group of alkali metals in the periodic table, the hardness of the metals generally decreases. This is due to the increasing atomic size and the weakening of metallic bonds, which makes the metals softer. For example, lithium is the hardest, while cesium is significantly softer. The increase in atomic radius results in less effective overlap of electron orbitals, contributing to the softer nature of the heavier alkali metals.
The nuclear charge decreases as you move down a group in the periodic table.
Down the group the size of atom increases. Hence the force of attraction between the nucleus and the electrons of the next atom decreases. Or in other words, the electronegativity decreases down the group.
The acidic character of oxides of group 15 elements decreases down the group because as we move down the group from nitrogen to bismuth, the ability of the oxide to donate protons decreases due to an increase in atomic size and metallic character, which results in a weaker acidity. Additionally, the anionic character of the oxide decreases as the metallicity of the element increases, leading to a less acidic nature of the oxides down the group.