No. Ukrainian is an East Slavic language, and things like Polish and Czech (both of which were spoken in Silesia, I'm not sure what 'Silesian' is supposed to be) are West Slavic.Actually, Silesian and Ukrainian are also close to South Slavic languages as well.
Now. It is true that ALL Slavic languages are pretty conservative, and that large chunks of vocabulary, for instance, are recognizable across the language families. Red/beautiful (krazni/a), numbers (edin,dva,...), city (g{o}rad), white (bel) for example. But 'all slavic languages are close to South Slavic' would be a better usage than picking individual examples.