Dr Karthick Raj AG thank you for your contribution to the discussion

As one moves down the group, the electropositive nature rises. Therefore, sodium is more electropositive than lithium and its size is larger as well. As a result, Sodium reacts with water more violently than Lithium. Sodium reacts violently with water because it is much more active than hydrogen. Although water is covalent, not ionic, it is helpful sometimes to consider water to be [H+][OH-], since after all hydrogen has a slight excess of positive charge. Sodium also floats on the surface, but enough heat is given off to melt the sodium (sodium has a lower melting point than lithium and the reaction produces heat faster) and it melts almost at once to form a small silvery ball that dashes around the surface. Lithium reacts fairly slowly, fizzing. Sodium reacts more quickly, generating enough heat to melt itself and to occasionally ignite the hydrogen gas, producing a yellow-orange flame characteristic of sodium. Sodium belong to group −1 of element i.e., alkali metal group. Due to high electropositive in nature cause low ionization enthalpy and also has low melting point. Hence when sodium put in water react violently to form NaOH aqnd H2. But the smaller size of the lithium ion corresponds to a larger charge density, and the lithium ion polarizes it environment stronger than the sodium ion. Sodium-ion batteries have several advantages over competing battery technologies. Compared to lithium-ion batteries, sodium-ion batteries have somewhat lower cost, better safety characteristics, and similar power delivery characteristics, but also a lower energy density. Basically, as you go down a group the elements are heavier because they contain more protons and neutrons in their nuclei. Lithium has lesser atomic weight than sodium. So, lithium has lesser density than sodium. Vapor pressure is inversely proportional to the intermolecular forces. Stronger the intermolecular forces lower will be the vapor pressure and vice versa. A liquid's vapor pressure is directly related to the intermolecular forces present between its molecules. The stronger these forces, the lower the rate of evaporation and the lower the vapor pressure. The vapor pressure of a liquid decreases as the strength of its intermolecular forces increases. Intermolecular forces determine bulk properties such as the melting points of solids and the boiling points of liquids. Liquids boil when the molecules have enough thermal energy to overcome the intermolecular attractive forces that hold them together, thereby forming bubbles of vapor within the liquid.