[mandy9008]

problem:
calculate the mass defect of the nitrogen nucleus ¹⁴₇N.
the mass of the neutral ¹⁴₇N is 14.003074 amu.

what i know:
mass defect=difference in mass between the nucleus of an atom and the sum of the separated particles that make up that nucleus.
mass of neutron=1.008665amu
mass of neutral H=1.007825amu

what i did:
14.003074amu - (1.008665amu + 1.007825amu)
=11.98

this is obviously not right, any help will be greatly appreciated!

[ARGOS++]

Dear mandy9008;

What is the ¹⁴ and the ₇ in front of N telling you?

And please don’t forget always the units (11.98 of what?) !!!

Good Luck!
                    ARGOS⁺⁺

[mandy9008]

the 14 is the mass number and the 7 is the atomic number...
and the units are amu

[ARGOS++]

Dear mandy9008;

But they tell you also:  # of nucleons = 14, and:   # of Protons = 7, -
   -  and that’s much more important for your calculation!

Good Luck!
                    ARGOS⁺⁺

[mandy9008]

okay. so when i solve for the nuclear binding energy(after i solve for the mass defect) i need the number of nucleons(14), but do i need it to solve for mass defect.
i know the answer is .1124amu
so, im not sure how to get to that number, i have tried every combination i can think of
      -adding the 2 masses and subtracting from the # of nucleons
      -"                                                               " # of protons
      -adding the 2 masses
      -subtracting the 2 masses
i am still stuck!!

[ARGOS++]

Dear mandy9008;

First:      What is # of nucleons minus # of Protons = 7 meaning?  It's equal the # of ??
Second:  How is mass defect defined?
Third:     The mass defect will come out as 0.112356 amu.

Good Luck!
                    ARGOS⁺⁺

[mandy9008]

got it!!

14-7=7
7(1.008665)+7(1.0078225)-14.003074
=.112356
=.1124

thank you so much!!

[ARGOS++]

Dear mandy9008;

Correct!

You 're welcome!   ─   Soon again.

Good Luck!
                    ARGOS⁺⁺