We present the large-scale clustering of emission line galaxies (ELG) from the Data Release 16 of the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey. The ELG sample contains 173,736 galaxies covering 1,170 square degrees in the redshift range 0.6 < z < 1.1. We perform a BAO measurement from the post-reconstruction power spectrum monopole, and study redshift space distortions (RSD) in the first three multipoles. Purely angular photometric systematics are mitigated by nulling angular signal in pixels of appropriate size. Variations of the redshift distribution with photometric conditions are accounted for by splitting and measuring the radial selection function of the survey in regions of homogeneous imaging. Both techniques result in integral constraints which we model consistently. At the effective redshift zeff = 0.845 we measure DV(zeff)/rdrag = 18.33 +0.57−0.62, with DV the volume averaged distance and rdrag the comoving sound horizon at the drag epoch. In combination with the RSD measurement, at zeff = 0.85 we find ƒσ8(zeff) = 0.289 +0.085−0.096, with ƒ the growth rate of structure and σ8 the normalisation of the linear power spectrum, DH(zeff)/rdrag = 20.0 +2.4−2.2 and DM(zeff)/rdrag = 19.17 ±0.99 with DH and DM the Hubble and comoving angular distances, respectively. Quoted errors include statistical and systematic contributions. We find good agreement with the results obtained in configuration space, thus allowing a consensus measurement of ƒσ8(zeff) = 0.315 ±0.095, DH(zeff)/rdrag = 19.6 +2.2−2.1 and DM(zeff)/rdrag = 19.5 ±1.0. This measurement is in agreement with a flat ΛCDM model with Planck parameters.