Pls help this is from the book physics for you

In all trials, the magnitude of the final velocity for g1 + g2 was less than the magnitude of any initial velocity. as mass increased, what happened to the velocity? the velocity decreased. the velocity increased. the velocity of g1 + g2 could not be measured. the velocity was not affected by the mass increase.

Atomic nuclei of almost all elements consist of

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