HELP ASAP Explain what is wrong with the following electron configurations. Then annotate the configuration to correct the error . a) 1s2 2s2 2p6 3s2 3p6 4s2 4d10 4p6
b) 1s2 2s2 2p6 3s3 3d5

Achemistry student weighs out 0.306 g of citric acid (h3c6h5o7), a triprotic acid, into a 250 ml volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with 0.1000 m naoh solution. calculate the volume of naoh solution the student will need to add to reach the final equivalence point. be sure your answer has the correct number of significant digits.