Name the factors that affect the thermal stability of alkali metal salts. Explain the stability trend observed in case of nitrates of these metals.
The thermal stability of a substance depends heavily on the structure of the substance which, in turn, is dependent on the bonds between atoms that hold that structure together. Group 1 nitrates decompose to form products: MeNO2 + O2 Going down Groups 1, nitrates become more stable. Higher temperatures are needed to decompose them. Cations (positively charged ions) can affect anions such as NO3-. They can lower the energy needed to break a N–O bond. This effect increases: • the smaller the cation • the greater the cation’s charge. The small positive ions at the top of the Group polarise the nitrate more than the larger positive ions at the bottom.