The element Sodium “Na” , has an atomic number 11 and atomic mass number equal to 22. When Na (11,22) undergoes beta-plus decay, it produces an element with atomic mass number equal to
The Correct Answer and Explanation is:
When sodium (Na) with an atomic number of 11 and an atomic mass number of 22 undergoes beta-plus decay (also known as positron emission), it transforms into a different element.
Step-by-step Explanation of Beta-Plus Decay:
In beta-plus decay, a proton in the nucleus of the atom is converted into a neutron, and a positron (which is the antimatter counterpart of an electron) along with a neutrino are emitted from the nucleus.
The key points to remember:
- The atomic number decreases by 1 because a proton is lost.
- The mass number stays the same because the proton is converted into a neutron.
Initial Element (Na):
- Atomic number = 11
- Mass number = 22
After Beta-Plus Decay:
- Atomic number = 11 – 1 = 10 (This corresponds to the element Neon (Ne)).
- Mass number remains 22, because the total number of nucleons (protons + neutrons) doesn’t change.
Thus, after beta-plus decay, the resulting element is Neon (Ne) with an atomic number of 10 and an atomic mass number of 22.
Resulting Element:
- Neon (Ne) with atomic number = 10 and mass number = 22.
In summary, the atomic mass number remains 22, and the element changes from Sodium (Na) to Neon (Ne) due to the conversion of a proton into a neutron.
