Classification ...

Which of the following statements are correct?

The smog is essentially caused by the presence of:

Which of the following order is incorrect.

The elements with atomic number 117 and 120 are yet to be discovered. In which group would you place these elements when discovered?

Consider 2 electronic configuration of potassium
$$K=1s^2,2s^2,2p^6,3s^2,3p^6, 4s^1$$
$$K=1s^2,2s^2,2p^6, 3s^2,3p^6,3d^1$$
find the effective nuclear charge experienced by last electron in (I) and (ii)

In long form of periodic table, the total number of periods  is:

The electronic configuration of an element is $$1s^22s^22p^63s^23p^63d^{10}4s^1$$. What is the atomic number of the next element of the same group?

Which of the following option is incorrect? 

Which of the following processes involves absorption of  energy?

Nuclides have: