Question

In an atom, there are 12 protons and 12 neutrons in the nucleus. Now, imagine that all the electrons are replaced with some hypothetical particles that have the same charge as electrons but are 500 times heavier. What effect will this replacement have on the atom’s:

1. Atomic number 
2. Atomic mass 
3. Mass number 
4. Overall charge

Answer 1

Given:

Number of protons = 12

Number of neutrons = 12

New particles have the same charge as electrons but are 500 times heavier.

1. The atomic number remains 12 because it depends only on the number of protons, which remains unchanged.
2. The atomic mass increases because the new particles are 500 times heavier than electrons, increasing the total mass of the atom.
3. Mass number = Number of protons + Number of neutrons
   \[ A=12+12=24 \]
   The mass number remains 24 because the numbers of protons and neutrons do not change.
4. The atom remains electrically neutral because the 12 new particles have the same negative charge as the original electrons, balancing the positive charge of 12 protons.