<u>Answer:</u> The correct option is A) They have fixed energy values.
<u>Explanation:</u>
Electron is one of the sub-atomic particle present around the nucleus of an atom which is negatively charged.
In an atomic model, it is assumed that the electron revolves around the nucleus in discrete orbits having fixed energy levels.
These electrons when jumping from one energy level to another, some amount of radiation is either emitted or absorbed.
These fixed energy levels are given by the Bohr model and thus, the electrons are quantized.
Hence, the correct option is A) They have fixed energy values.
Appropriate symbol for an isotope of potassium - 39 corresponding to the isotope notion r A ZX
FeS is an example of an ionic compound as in the formula there is a metal of Fe iron chemically bonded to the nonmetal S sulphur. Resulting in a strong electrostatic attraction due to the transfer of valence electrons from the iron to the Sulphur.
The electromagnet and the permanent magnet -- interact with each other as any two magnets do. The positive end of the electromagnet is attracted to the negative pole of the permanent magnetic field, and the negative pole of the electromagnet is repelled by the permanent magnet's negative pole
