The spin of fundamental particles determines if they are bosons or fermions. The atoms also have bosonic or fermionic behavior, for example $^4$He has bosonic and $^3$He has fermionic statistics. Which quantity of atom determines its statistics?

The spin of fundamental particles determines if they are bosons or fermions. The atoms also have bosonic or fermionic behavior, for example $\require{mhchem}\ce{^4He}$ has bosonic and $\ce{^3He}$ has fermionic statistics. Which quantity of atom determines its statistics?

The spin of fondamental particles determines if they are bosons or fermions. The atoms also have bosonic or fermionic behavior, for example He4 has bosonic and He3 has fermionic statistics. Which quantity of atom determines its statistics?

The spin of fundamental particles determines if they are bosons or fermions. The atoms also have bosonic or fermionic behavior, for example $^4$He has bosonic and $^3$He has fermionic statistics. Which quantity of atom determines its statistics?