Answer:
1 = strontium
2 = technetium
3 = silver
Step-by-step explanation:
Strontium is present in 2 group of periodic table. It is alkaline earth metal. It is most reactive element and can not found free in nature. it is insoluble in water but react with water and form strontium hydroxide and hydrogen gas is also produced. It is radioactive element.
It is similar to the calcium and can incorporated into bones. The food rich with strontium is used to avoid the osteoporosis. It is found in leafy vegetables, grains, sea foods etc.
In given series strontium is highest in reactivity then technetium, while the technetium is more reactive than silver. The silver is less reactive as compared to both given elements.