It takes 153 years for half of a sample of silicon (si) atoms with 14 protons, 14 electrons, and 18 neutrons to decay. what is the name of this specific silicon isotope?

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?