Question

What element decays into sodium-23 though beta decay?

Answer 1

Both neon-23 and magnesium-23 decay into sodium-23 by beta decay.

There are two types of beta decay:

• β⁻ decay is a process in which a nucleus emits an electron.
• β⁺ decay is a process in which a nucleus emits a positron — the antimatter counterpart of an electron.

β⁻ DECAY

The nuclear symbol for a β⁻ particle is `""_-1^0"e"`.

In any nuclear equation, the sum of the subscripts (atomic numbers, Z) and the sum of the superscripts (atomic masses, M) must be equal on each side of the equation.

For formation of sodium-23 by β⁻ decay, we must have

? → ₁₁²³Na + ₋₁⁰e

M = 23 + 0 = 23
Z = 11 - 1 = 10

The element with Z = 10 is Ne.

So the equation is

₁₀²³Ne → ₁₁²³Na + ₋₁⁰e

Note that, in β⁻ decay, the product has the same mass number but an atomic number that has increased by 1.

Neon-23 decays by β⁻ decay to sodium-23 with a half-life of about 37 s.

β⁺ DECAY

The symbol for a β⁺ particle is `""_1^0e`.

For the formation of sodium-23 by β⁺ decay, we must have

? → `""_11^23"Na" + ""_1^0e`

M = 23 + 0 = 23
Z = 11 + 1 = 12

The element with Z = 12 is Mg.

So the equation is

`""_12^23"Mg" → ""_11^23"Na" + ""_1^0e`

Note that, in β⁺ decay, the product has the same mass number but an atomic number that has decreased by 1.

Magnesium-23 decays by β⁺ decay to sodium-23 with a half-life of about 11 s.