तृतीय आवर्त का तत्त्व है-

Yes, I can provide the step by step solution for the given question. तृतीय आवर्त का तत्त्व है- Step 1: Translate the given statement in English as "What is the element of the third period?" $\text{What is the element of the third period?}$ Step 2: Recall the periodic table and identify the third period. $\text{Periodic table:}$$\text{H He}$$\text{Li Be B C N O F Ne}$$\text{Na Mg Al Si P S Cl Ar}$$\text{K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr}$$\text{Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe}$$\text{Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn}$$\text{Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og}$$\text{The third period is: Li Be B C N O F Ne}$ Step 3: Identify the element in the third period. $\text{The element in the third period is: Na}$ Step 4: Write the answer in Hindi. $\text{तृतीय आवर्त का तत्त्व है: Na}$ Therefore, the answer to the given question is "Na" (नाइट्रोजन).