Can i have some information on calcium (element in periodic table) please

An electron is trapped at a defect in a crystal. the defect may be modeled as a one-dimensional, rigid-walled box of width 1.00 nm. (a) sketch the wavefunctions and probability densities for the n 1 and n 2 states. (b) for the n 1 state, nd the probability of nding the electron between x1 0.15 nm and x2 0.35 nm, where x 0 is the left side of the box. (c) repeat (b) for the n 2 state. (d) calculate the energies in electron volts of the n 1 and n 2 states

Which of the following can enter and exit a closed system? a. matter and energy b. neither energy nor matter c. matter but not energy d. enrgy but not matter

Jaylen is a championship runner of the school's track team. during one of his trials, his speed was measured at 15.1 m/s. find jaylen's kinetic energy during that trial if his mass is 54.6 kg.