Please somebody help! (its fill in the blanks)

Which of the following are considered noble gases? a. bromine b. neon c. argon d. chlorine

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?

Which is the correct symbol for an isotope of iodine with 53 protons and 78 neutrons?