[填空题]
Alkali metals react w-g)p 3iy6yjf+bmjxss- j9kl; ds ohcqt ;g+t;a/k0b)ith water to form metal hydroxide and hydrogen gas.
1.Write a balanced equation between sodium and water.
2.Explain why this reaction is considered as a redox reaction.
3.3 other alkali metals W, X and Y also react with water.
Based on the following observations, arrange the metals in order, starting from the weakest oxidizing agent. Explain your answer. $\lt$ $\lt$ $\lt$