To determine the number of neutrons in selenium (Se), we first need to know its atomic number and atomic mass. Selenium has an atomic number of 34, which means it has 34 protons.
The atomic mass of selenium is approximately 78.96. Since the atomic mass is a weighted average of all the isotopes of an element, it is not a whole number. However, for simplicity, we can round it to 79.
To find the number of neutrons, we can use the following formula:
Number of Neutrons = Atomic Mass – Atomic Number
Applying the numbers:
Number of Neutrons = 79 – 34 = 45
Therefore, selenium has approximately 45 neutrons.