Question 3 of 62beginner💡 UnderstandShort Answer2 marks

How many neutrons and protons are there in the following nuclei? ¹³₆C, ¹⁶₈O, ²⁴₁₂Mg, ⁵⁶₂₆Fe, ⁸⁸₃₈Sr

Correct Answer

(¹³₆C) Protons = 6, Neutrons = 7

(¹⁶₈O) Protons = 8, Neutrons = 8

(²⁴₁₂Mg) Protons = 12, Neutrons = 12

(⁵⁶₂₆Fe) Protons = 26, Neutrons = 30

(⁸⁸₃₈Sr) Protons = 38, Neutrons = 50

Exercise: EXERCISES | Q: 2.3 | (Page 41)
For More Understanding

Explanation

To find the number of protons and neutrons in a nucleus, we use its symbol ZAX^{A}_{Z}\text{X}. The subscript ZZ represents the atomic number, which is equal to the number of protons. The superscript AA represents the mass number, which is the sum of protons and neutrons. Therefore, the number of neutrons is calculated as A−ZA - Z.

For 613C^{13}_{6}\text{C}, protons = 6, neutrons = 13−6=713 - 6 = 7. For 816O^{16}_{8}\text{O}, protons = 8, neutrons = 16−8=816 - 8 = 8. For 1224Mg^{24}_{12}\text{Mg}, protons = 12, neutrons = 24−12=1224 - 12 = 12.

For 2656Fe^{56}_{26}\text{Fe}, protons = 26, neutrons = 56−26=3056 - 26 = 30. For 3888Sr^{88}_{38}\text{Sr}, protons = 38, neutrons = 88−38=5088 - 38 = 50. This method applies the fundamental relationship between atomic mass, atomic number, and subatomic particles.

Solution Steps

  1. Step 1: For 613C^{13}_{6}\text{C}, Z=6Z = 6, A=13A = 13. Protons = 6, Neutrons = 13−6=713 - 6 = 7.

  2. Step 2: For 816O^{16}_{8}\text{O}, Z=8Z = 8, A=16A = 16. Protons = 8, Neutrons = 16−8=816 - 8 = 8.

  3. Step 3: For 1224Mg^{24}_{12}\text{Mg}, Z=12Z = 12, A=24A = 24. Protons = 12, Neutrons = 24−12=1224 - 12 = 12.

  4. Step 4: For 2656Fe^{56}_{26}\text{Fe}, Z=26Z = 26, A=56A = 56. Protons = 26, Neutrons = 56−26=3056 - 26 = 30.

  5. Step 5: For 3888Sr^{88}_{38}\text{Sr}, Z=38Z = 38, A=88A = 88. Protons = 38, Neutrons = 88−38=5088 - 38 = 50.

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