calculate the mass defect of Helium `[""._(2)He^(4)]`
mass of proton `=1.007276 u,`
Mass of neutron `=1.008665u,`
Mass of `""._(2) He^(4)= 1.001506 u,`

Explanation

To calculate the mass defect of Helium-4 \((\text{He}^{4}_{2})\), we will follow these steps:

### Step 1: Identify the number of protons and neutrons in Helium-4
Helium-4 has:
- Atomic number (number of protons) = 2
- Mass number = 4

To find the number of neutrons:
...