Practice MCQ Questions and answers on Chemistry-GK

l = 2 corresponds to d orbitals which can take upto 10 electrons.

Spin quantum number is the is the fourth quantum number that differentiates two electrons in the same orbital. The Pauli exclusion principle states that “no two electrons in an atom can have the same four quantum numbers. This means that no two electrons can have the same state in an atom. Each electron must have a different spin or occupy a different shell from any other.

When cathode rays strike a solid target of high atomic weight and high melting point such as tungsten, molybdenum, etc, they give rise to a highly penetrating radiation called the X-rays (LIT Physics by Dr. P.K Agarwal).

10 electrons can be accommodated in d-orbital.

In 1932 Carl Anderson, a young professor at the California Institute of Technology in the US, was studying showers of cosmic particles in a cloud chamber and saw a track left by "something positively charged, and with the same mass as an electron".

When there are two electrons in the same orbital, they have opposite spins. The Pauli exclusion principle states that there can only be a maximum of two electrons for every one orientation, and the two electrons must be opposite in spin direction; meaning one electron has ms=+21 and the other electron has ms=−21.

The positron is the antiparticle to the electron. The positron has the same rest mass as the electron but opposite charge, one positive elementary charge.

In quantum chromodynamics, nucleons are regarded as composites of three quarks (elementary particles) and pions are composites of two quarks. According to EOB’s rules, nucleons move as fermions while pions move as bosons.

When an electric field is applied, both the valence electrons and the free electrons move in the same direction. The hole direction is opposite to that of valence electron but the mobility is the same. Even for the same electric field, valence electrons cannot move as freely as the free electrons because its movement is restricted due to collisions. Therefore, the velocity of valence electrons is less compared to free electrons. In other words, the velocity of holes is less compared to free electrons. This means mobility is also less for a hole compared to free electron.

Neutron has greatest mass. Proton is a subatomic particle with symbol p and positive electric charge of +1 elementary charge and mass slightly less than that of neutron.