Answer:
K°(g)* + 419 Kj/mole => K⁺(g) + e⁻
Step-by-step explanation:
1st ionization step for potassium is the ionization of the 4s¹ electron. This requires 419 Kj/mole energy (endothermic). The reaction equation is ...
K°(g)* + 419 Kj/mole => K⁺(g) + e⁻
*note: Ionization of group IA metals requires they be in gas phase. That is, as shown by the Born-Haber Cycle** for formation of ionic compounds ...
K°(s) + 89.24 Kj/mole => K°(g); then ...
K°(g) + 419 Kj/mole => K⁺(g).
**Recommend review of Born-Haber cycle for formation of ionic compounds.