How many beauteous does element X have if it's atomic number is 24 and it's mass number is 78

Answer;

54 neutrons

Explanation; Atomic number of an atom is the number of protons in its nucleus. Since protons are positively charged, it makes the nucleus to be positively charged. A neutral atom has equal number of protons and electrons, thus the atomic number of a neutral atom is also equivalent to the number of electrons. Mass number of an atom is the sum of protons and neutrons in the nucleus of the atom. Therefore, to get the number of neutrons we subtract the atomic number from the mass number. That is; 78 - 24 = 54 neutrons.