Answer
No, it won't be the same element: P will become Si.
Work Step by Step
A positron is a positively-charged electron.
The atomic number decreases by 1 for positron emission, because positrons carry a charge of +1e.
Phosphorus has an atomic number of 15, so it transmutes to silicon, which has an atomic number of 14.
This is discussed on pages 628-629. The periodic table on page 216 is also helpful.
