Which element is placed in the same period as ruthenium but has a higher atomic number than it? bismuth osmium silver zirconium

Answer is: 3) silver.

Ruthenium (Ru) is in period 5 and has atomic number 44.

1) Bizmuth (Bi) has atomic number 83, but it is in period 6.

2) Osmium (Os) has atomic number 76, but it is in period 6.

3) Silver (Ag, from the Latin argentum) has atomic number 47 and it is in period 5.

4) Zirconium (Zr) has atomic number 40.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

b. is the answer hoped i