Stereoisomers are isomers that have the same atom to atom connectivity but differ in the arrangement of atoms or groups in space.
Glucose and galactose are stereoisomers that have more than one stereogenic center but differ in the configuration of atoms and groups about one of the stereogenic centers. This kind of stereoisomers are also called epimers.
Glucose and galactose differ in the orientation of -H and -OH at carbon-4.
Explanation: Carbon and silicon BOTH come from Group 14 of the Periodic Table , i.e. both formally have the same number of valence electrons, 4 such electrons.........