Help me fill out the blank spots

Will mark brainliest how many electrons can be held in the energy level n = 4?

Which of the following is a conclusion that resulted from ernest rutherford’s scattering experiment? (will mark brainliest) a. the nucleus is negatively charged b. the atom is a dense solid and is indivisible c. the mass is conserved when atoms react chemically d. the nucleus is very small and the atom is mostly empty space

Is 343 in the sequence -5, -2, 1, 4, 7