Laboratoire de Physique Théorique et Hautes Energies, 3 Universités Pierre et Marie Curie (Paris 6) et Denis Diderot (Paris 7);Unité associée au CNRS D0 280.Abstract: I study the scalar representations of the electroweak group of the Standard Model, which is a subgroup of the chiral group U (N ) L × U (N ) R with N flavours, for N even, with a special emphasis on their chiral properties and on their behaviour by the discrete symmetries P and CP . They exhaust the 2N 2 scalar and pseudoscalar degrees of freedom of the chiral group, for which a SU (2) L × U (1) renormalizable, anomaly-free gauge theory naturally springs out. It is shown to have a global diagonal SU (2) V symmetry independently of the value of the hypercharge coupling, which becomes local at the limit when the latter vanishes. When acting in the 4-dimensional space of states spanned by the special representations under scrutiny in this paper, the electric charge is one of the three generators of this "custodial" symmetry; that the latter stays an unbroken symmetry is thus correlated with the quantization of the electric charge.PACS: 02.20. 11.30.Er, 11.30.Rd, 12.15