Choose the right form of the Participle. 1.A positively (charging, charged, having charged ) particle having the mass of the electron was discovered in 1932. 2. The scientist found that the substances (produced, producing, having produced) were complex. 3. According to this theory (dealt with, dealing with, having been dealt with) atomic structure nucleus is a very small, compact, central part of an atom. 4. Elements (composed, composing, having been composed) of atom containing only one or two valence electrons usually form positive ions. 5. (Investigated, investigating, having investigated) this phenomenon the scientist can make some important conclusions. 6. When freshly (prepared, preparing, having prepared) this solution is colorless.