At 1990 K and 1 atm pressure there are equal number of Cl₂ molecules and Cl atoms in the reaction mixture. The value of K_p for the reaction ${\mathrm{Cl}}_{2\left(\mathrm{g}\right)}\rightleftarrows 2{\mathrm{Cl}}_{\left(\mathrm{g}\right)}$ under the above conditions is $\mathrm{x}\times {10}^{-1}$.The value of x is______