Why is the enthalpy of atomisation also the bond enthalpy?

Question

My book says that the enthalpy of atomisation is the enthalpy change when one mole of its atoms in the gaseous state is formed from the element under standard conditions.

eg. C(graphite)➙ C(g)

That is all alright.

 

But then it talks about bond enthalpy and then says,

 CH4(g) ➙ C(g) + 4H(g) is the reaction for atomisation of CH4(g)

 

How does this fit the definition of enthalpy of atomisation?? Coz it is defined when one mole of its gaseous atoms is formed from its elements. 

 The reaction doesn't look like atomisation at all.               

Answer 1

CH4 (methane) is formed from C(g) and 4H(g), so if you look at the reverse reaction, you see that CH4 is formed from 1 mole of C and 4 moles H both in the gaseous state.  The energy needed to break the 4 C-H bonds in methane will be the same as the energy generated when C(g) + 4H(g) combine to form CH4.  Not sure if this answers your question, but that's my take on the problem.