In this work, through density functional theory (DFT) calculations, we propose that alkali metals have a richer chemistry than what thought. By calculating the electronic structures of the alkali fluorides NaF, KF, RbF and CsF, we will present evidence that the heavier elements, K, Rb and Cs should be considered as 7 valence electrons elements already at few GPa of pressure, while retaining an oxidation state of +1, and in some cases, like in CsCl, even at ambient conditions, with profound implication for the chemistry of alkali metals. Additionally, we will also propose ways to observe and measure chemical bonds formed by the semi-core orbitals.