What is the answer for K pls help

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

How many grams of magnesium metal will react completely with 8.3 liters of 5.5m hcl? show all work

Afusion reaction takes place between carbon and another element. neutrons are released, and a different element is formed. the different element is a) lighter than helium.b)heavier than helium.c)the same weight as helium.d)dependent on the element that reacted with carbon.