1. In a single atom, no more than 2 electrons can occupy a single orbital? A. True
2. The maximum number of electrons allowed in a p sublevel of the 3rd principal level is?
B.6
3. A neutral atom has a ground state electronic configuration of 1s^2 2s^2. Which of the following statements concerning this atom is/are correct?
B. All of the above.

Actually Welcome to the Concept of the Projectile Motion.
Since, here given that, vertical velocity= 50m/s
we know that u*sin(theta) = vertical velocity
so the time taken to reach the maximum height or the time of Ascent is equal to
T = Usin(theta) ÷ g, here g = 9.8 m/s^2
so we get as,
T = 50/9.8
T = 5.10 seconds
thus the time taken to reach max height is 5.10 seconds.
a). Water is still H₂O after it freezes.
b). Ice is still H₂O after it melts.
c). Wire is still Cu when it's bent.
d). Paper combines with the O₂ in the air, and turns into
a lot of new compounds when it burns.