The number of protons, neutrons and electrons in ${}_{71}{}^{175}\mathrm{Lu}$, respectively, are:

1.  104, 71 and 71

2.  71, 71 and 104

3.  175, 104 and 71

4.  71, 104 and 71 

An element X has the following isotopic composition : 
²⁰⁰X: 90% 
¹⁹⁹X: 8.0% 
²⁰²X: 2.0% 
The weighted average atomic mass of the naturally-occurring element X is closest to:

1. 200 amu
2. 201 amu
3. 202 amu
4. 199 amu

The nuclei of which one of the following pairs are isotones :

1.   ₃₄ ${\mathrm{Se}}^{74}{,}_{31}{\mathrm{Ga}}^{71}$

2.  ${}_{38}{\mathrm{Sr}}^{84}{,}_{38}{\mathrm{Sr}}^{86}$

3.  ${}_{42}{\mathrm{Mo}}^{92}{,}_{40}{\mathrm{Zr}}^{92}$

4.  ${}_{20}{\mathrm{Ca}}^{40}{,}_{16}{\mathrm{S}}^{32}$