We study the settling of small but heavy particles in a rectangular two-dimensional Rayleigh-Benard system at a fixed Rayleigh number Ra = 10⁵ and Prandtl number Pr = 0.701. Considering one-way particle-fluid coupling, we define a length scale called particle boundary layer thickness δ_p. Particles which are initialised below δ_p, settle quickly under gravity and the remaining particles form quasi-static clouds. The rate of particle settling after the time scale t/τ_r ~ Ο(1) (t is time, τ_r is the particle residence time) is low. Numerical results show that the total fraction of particles that settle and δp increase monotonically with increase in the particle Stokes number St_p. However, the horizontal distance between the two adjacent particle clouds Δ and the size of each particle cloud reduce with an increase in the Stokes number. The number of particles that settle on the bottom surface with time deviates significantly from the expected exponential law and they settle at a substantially slow rate for small Stokes numbers.