Question

in C^12 atom if mass of e- is doubled and mass of proton is halved then calculate the percentage change in mass no. of C^12

Answer 1

0

Answer 2

The mass number (A) of an atom is defined as the total number of protons and neutrons in its nucleus. It is given by the formula A = Z + N, where Z is the atomic number (number of protons) and N is the number of neutrons.

For a C-12 atom:

• The atomic number (Z) is 6, which means it has 6 protons.
• The mass number (A) is given as 12.
• The number of neutrons (N) is calculated as A - Z = 12 - 6 = 6.

So, a C-12 atom has 6 protons and 6 neutrons in its nucleus.

The question describes a hypothetical scenario where the mass of an electron is doubled and the mass of a proton is halved. These changes refer to the intrinsic mass of the particles themselves.

The mass number is a count of the number of protons and neutrons in the nucleus. It does not depend on the individual masses of these particles or the mass of electrons.

Under the hypothetical conditions:

• The number of protons in the C-12 atom remains 6. The identity of the element (Carbon) is determined by the number of protons.
• The number of neutrons in the C-12 atom remains 6. The specific isotope C-12 has 6 neutrons.
• The number of electrons in a neutral atom is equal to the number of protons, which is 6. (Although electrons do not contribute to the mass number).

The hypothetical changes in the masses of the electron and proton do not change the number of protons and neutrons in the nucleus of the C-12 atom.

Therefore, the new mass number of the C-12 atom under these hypothetical conditions is still the sum of the number of protons and neutrons: New mass number = Number of protons + Number of neutrons = 6 + 6 = 12.

The original mass number of C-12 was 12. The new mass number is 12.

The change in mass number = New mass number - Original mass number = 12 - 12 = 0.

The percentage change in mass number is calculated as: Percentage change = ((New mass number - Original mass number) / Original mass number) * 100 Percentage change = (0 / 12) * 100 = 0%.

The mass number of C-12 remains unchanged despite the hypothetical changes in the masses of its constituent particles.