The number of protons in an atom identifies the Atomic Number
Hope it helps!
As per Kepler's third law we know that

now here we know that
= year of Neptune
= year of Earth
= distance of Neptune from Sun
= Distance of Earth from Sun
so now we will have



so length of year of Neptune is 164.3 years
Answer:
h = 51020.40 meters
Explanation:
Speed of the rifle, v = 1000 m/s
Let h is the height gained by the bullet. It can be calculated using the conservation of energy as :


h = 51020.40 meters
So, the bullet will get up to a height of 51020.40 meters. Hence, this is the required solution.
Im guessing it's (a) since the numbers go in chronological order and you read the periodic table left to right