Why are electrons shared equally in the Ozone and unequally in carbon dioxide?

The ozone molecule consists of 3 oxygen atoms, and all oxygen atoms have exactly the same attraction for electrons (technically called electronegativity) so naturally, they share electrons equally. The carbon dioxide molecule consists of one carbon atom and two oxygen atoms. Carbon does not attract electrons as strongly as oxygen does (it has a lower electronegativity) so therefore the electrons are not shared equally.