Chemistry questions

Question

Determine which of the following electron configurations are not valid. If it is invalid, EXPLAIN WHY!

33) [Ra] 7s25f8

34) [Kr] 5s24d105p5

35) [Xe]

Answer 1

33) [Ra] 7s²5f⁸ No; [ ] are for the Noble gases and Ra is not a Noble gas

Rn is a Noble gas that would fit this. If you continue from Rn through 7s² then 5f⁸ is a proper order and 5f⁸ is Cm - number 96

34) [Kr] 5s²4d¹⁰5p⁵ Yes; going from Kr to 5s² 4d¹⁰ 5p⁵ is a correct order(sequence) and 5p⁵ is Iodine number 53

35) [Xe] No: this is just the Noble gas Xenon - electron configuration includes a Noble gas before the element you are representing. So if Xenon is what you are representing it should be [Kr] 5s² 4d¹⁰ 5p⁶