Polonium has a mass number of 212 and an atomic number of 84. In a balanced nuclear reaction, polonium releases an alpha particle to produce lead. Which option is the atomic number of lead?.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

the answer is 0.42 is that is an option. this question provides no info