What’s the missing particle in the following nuclear reaction?
$$\boldsymbol{\mathrm{{}^2_1H+{}^{63}_{29}Cu\to {}^{64}_{30}Zn+(?)}}$$
A) proton
B) neutron
C) electron
D) positron
E) deuteron
A) proton
B) neutron
C) electron
D) positron
E) deuteron
In order to balance the mass number (the superscripts), we must have $2+63= 64+A$, so $A=1$. In order to balance the charge (the subscripts), we need $1+29=30+Z$, so $Z=0$. A particle with a mass number of 1 and no charge is a neutron, $\mathrm{{}^1_0n}$.