How many neutrons are present in an atom of 226Ra?

• A. 226
• B. 88
• C. 138
• D. 144

Answer: (C)

Verified step by step guidance

1. Identify the atomic number (Z) and the mass number (A) of the atom. The atomic number is the number of protons, and the mass number is the total number of protons and neutrons. For 226Ra, the atomic number is 88 and the mass number is 226.
2. Recall the relationship between mass number, atomic number, and number of neutrons: \(\text{Number of neutrons} = A - Z\).
3. Substitute the given values into the formula: \(\text{Number of neutrons} = 226 - 88\).
4. Perform the subtraction to find the number of neutrons (do not calculate the final value here, just set up the expression).
5. Interpret the result as the number of neutrons present in the atom of \(^{226}\text{Ra}\).