  The STAR experiment at RHIC has completed its first phase of the Beam Energy
Scan (BES-I) program to understand the phase structure of the quantum
chromodynamics (QCD). The bulk properties of the system formed in Au+Au
collisions at different center of mass energy $\sqrt{s_{NN}} = $ 7.7, 11.5,
19.6, 27, and 39 GeV have been studied from the data collected in the year 2010
and 2011. The centrality and energy dependence of mid-rapidity ($|y|$ < 0.1)
particle yields, and ratios are presented here. The chemical freeze-out
parameters are extracted using measured particle ratios within the framework of
a statistical model.
