If Am-243 alpha decays, what would it turn into? Your answer must be in the following notation. Symbol - Mass Number example = Al-27 Include the - with no spaces between it and the symbol or the mass number. If S-35 beta decays, what would it turn into? Your answer must be in the following notation. Symbol - Mass Number example = Al-27 Include the - with no spaces between it and the symbol or the mass number.