The nucleus of an isotope of phosphorus ($P$) has a relative charge of $+15$. The relative mass of the nucleus is $32$.

Complete the symbol for this isotope of phosphorus by identifying the mass number $A$ and atomic number $Z$ in the symbol ${}_Z^{A}P$.

A nucleus of this isotope emits beta-minus (${\beta }^{-}$) radiation. State the values for the relative charge and relative mass of the nucleus after this radiation is emitted.

The table below shows some information for two different isotopes of phosphorus, labelled X and Y.

Complete the sentences below to describe the nucleus of isotope X and the nucleus of isotope Y. Use phrases from the list:

• less than Y

• more than Y

• the same as Y

• The number of protons in the nucleus of X is ............

• The number of neutrons in the nucleus of X is ............

An agricultural researcher uses a radioactive tracer to study how quickly a plant absorbs phosphorus through its roots. A small amount of the tracer is added to liquid fertilizer in the soil, and a detector is placed outside the plant's stem and leaves to measure the radiation emitted.

Which type of radiation (alpha, beta, or gamma) is most suitable for this tracer to be detected outside the plant stem and soil? Give one reason for your choice.

The researcher can choose between isotopes with three different half-lives:

• 10 seconds
• 14 days
• 50 years

The researcher chooses the isotope with a half-life of 14 days. Suggest two reasons why 14 days is the most suitable half-life.