If a system has 5.00×10^2 kcal of work done to it, and releases 5.00×10^2 kJ of heat into its surroundings, what is the change in internal energy (Δ or Δ) of the system?

catya your not at all which answer i've seen you do this on another question!

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8