Classification ...

Which of the following will have lowest electron affinity?

Why do noble gases have positive electron gain enthalpy?

Which of the following is not a periodic property for the elements?

Few values of enthalpies are given below:
$$O = - 141 \ kJ\ mol^{-1}$$, $$F = - 328\ kJ \ mol^{-1}$$
$$S = - 200 \ kJ \ mol^{-1}$$, $$CI = - 349 \ kJ \ mol^{-1}$$
What do these values show?

The electronic states $$X$$ and $$Y$$ of an atom are depeicted below:
$$X : 1s^{2} 2s^{2} 2p^{6} 3s^{1}$$
$$Y: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{1}$$
Which of the following statements is not correct?

Which of the following gases is most predominating in the Sun?

Which of the following arrangements represents the correct order of electron gain enthalpy?

Why is the electron gain enthalpy of O or F less than that of S or CI?

Choose the correct answer form the alternatives given. $$Ca^{2+}$$ is isoelectronic with:

The main reason for showing anomalous properties of the first member of a group in s or p-block is :