The number of elements

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

In which of these cases are the two wave points considered to be in phase with each other?

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?