Answer: Option (3) is the correct answer.
Explanation:
When a more reactive element or atom replaces a less reactive atom then this type of reaction is known as single displacement reaction.
In the given reaction, potassium iodide reacts with fluorine and results in the formation of potassium fluoride and iodine.
Here, fluorine being more reactive displaces iodine from potassium iodide.
Therefore, it is a single replacement or displacement reaction.
Answer: -
²²³Ra is the daughter nuclide produced when ²²⁷Th undergoes alpha decay
Explanation: -
When alpha decay occurs, the mass number of the parent decreases by 4 and the atomic number decreases by 2.
Mass number of ²²⁷Th =227
Atomic number of ²²⁷Th = 90
Mass number of daughter = 227 - 4 = 223
Atomic number of daughter = 90 - 2 = 88
88 is the atomic number of Ra Radium.
Thus the daughter is ²²³Ra
Many atoms if they are radioactive isotopes will loss protons and neutrons as radiation in order to gain and become more stable
hope that helps