Abstract: To date, telluro-ketones [H2A=Te; A=C, Si and Ge] have not been synthesized although there are reports for the existence of their complexes. The elusive existence of such isolated monomeric heavy ketones has been ascribed to the semipolar character of both their σ and π bonds due to which they tend to undergo polymerization or other addition reactions, unless bulky or stabilizing substituents are present. Therefore the objectives of this research have been the:1) exploration of the molecular parameters (bond lengths and bond angles), ionization potentials (IPad and IPad(ZPVE)), electron affinities (EAad, EAad(ZPVE), VEA and VDE), Kohn–Sham HOMO–LUMO gaps and singlet–triplet gaps of the mentioned telluro-ketones, 2) investigation of the reaction pathways for the isomerization and decomposition reactions of H2A=Te and HFA=Te (A=C, Si and Ge) molecules on their singlet state PES,3) evaluation of the A=Te bond dissociation energies as well as the σ- and π-bond energies and their standard heats of formation (ΔHf°) to gain more confidence on the reactivity and thermodynamic stability of these telluro-ketones,4) investigation of the nature, reactivity, and stability of the A=Te and A-Te bonds with respect to C=E (E=O, S and Se) bonds.Since experimental data are still lacking for these molecules, the findings of this work should add to the literature and assist the experimental community to synthesize, isolate and further explore the properties of these novel telluro-ketones.