sign of electron affinity

[Emily Widjaja 3A]

Hello,

In the textbook, its written that first electron affinity is positive since energy is released when an electron is added to a neutral atom, and that second electron affinity is negative, as energy would need to be supplied to [censored] another electron to an anion. However, in the textbook example about adding electrons to an oxygen atom, it was written that, and I quote:

"In fact, 104 kj/mol is released when the first electron adds to the neutral atom O to form O-, but 844 kj/mol must be supplied to add a second electron to form O2-, so the total energy required to make O2- from O is +703 kj/mol. "

Shouldn't the total energy be -703 instead of 703, since 844 kj/mol is negative as it is the second electron affinity?

[amar_151]

In the last part of the question, it says that the total amount of energy REQUIRED is +703 kJ. You are correct that it would be a negative value, so long as we use the wording "total amount of energy released is -703 kJ".