# Question 51e16

Sep 9, 2016

A. The mass number of the original nucleus changes.

#### Explanation:

An atom undergoes β-decay because it is unstable.

When it decays,

C. The original nucleus approaches greater stability

and

D. Energy is released.

A typical β-decay reaction is

""_6^14"C" → ""_7^14"N" +color(white)(l) _text(-1)^0"e" + bar(ν)_e#

B. The atomic number of the original nucleus changes (from 6 to 7)

but

A. The mass number of the original nucleus stays the same (at 14).

Therefore A is the incorrect statement.