Why is the first ionisation energy of Potassium less than Sodium?
The first ionisation energy is the energy required to move one mole of electrons from one mole of atoms in its gaseous state.
The outer electron in Potassium is in the 4s orbital, which is further away from the nucleus than the 3s orbital of the Sodium. The greater distance means that the attraction between the electron is weaker.
The electron in Potassium is also more affected by shielding due to more shells, further weakening this attraction. This means that less energy is needed to remove the outermost electron and therefore the ionisation energy is lower.
AR
Related Chemistry A Level answers
All answers ▸Calcium nitride contains 81.1% by mass of the metal. Calculate the empirical formula of calcium nitride. Show your working.
Given is a following reaction at equilibrium: N2(g) + 3H2(g) ⇄ 2NH3(g), ΔH < 0. What will be the effect of changing the following conditions on the system? 1. Increasing pressure. 2. Decreasing temperature. 3. Adding a catalyst. 4. Adding HCl(g).
1.5 g of hydrocarbon undergoes complete combustion to give 4.4 g of CO2 and 2.7 g of H2O. Given this data, what is the empirical formula of this hydrocarbon?
Define the term Covalent Bond