NEET Practice Questions (MCQs) with Answers & Solutions

First, we need to convert the mass of Cs to moles: \[ \text{Moles of Cs} = \frac{\text{mass}}{\text{molar mass}} = \frac{2.66 \text{ mg}}{133 \text{ g/mol}} \] Since 1 mg = 0.001 g, \[ \text{Moles of Cs} = \frac{2.66 \times 10^{-3} \text{ g}}{133 \text{ g/mol}} \approx 2 \times 10^{-5} \text{mol} \] The ionization enthalpy of Cs is given as 375.6 kJ/mol. Therefore, the energy required to convert 2.66 mg of Cs to \( Cs^+ \) is: \[ \text{Energy} = \text{moles} \times \text{ionization enthalpy} = 2 \times 10^{-5} \text{ mol} \times 375.6 \text{ kJ/mol} \] \[ \text{Energy} = 7.512 \text{ J} \] Thus, the correct option is 7.512 J.

If P is a halogen (from Group 17), it has 7 valence electrons. Since N has an atomic number of x-1, it would most likely be an alkali metal with 1 valence electron. The bond between an alkali metal and a halogen is typically ionic due to the transfer of the electron from the metal to the halogen. Therefore, the bond between N and P is ionic.

An element in Group 16 and the 5th period of the periodic table is Tellurium (Te), which has an atomic number of 52. Thus, the correct option is 52.

Element with atomic number 114 is known as Flerovium (Fl). It belongs to the 7th period and group 14 of the periodic table.

The size of Molybdenum (Mo) is very similar to Tungsten (W) due to the poor shielding effect by 4f electrons. The poor shielding results in a higher effective nuclear charge, causing the atomic radii to be similar.

The order of ionization energy for the elements K (Potassium), Ca (Calcium), and Ba (Barium) can be explained based on their positions in the periodic table. Ionization energy typically increases across a period and decreases down a group. Calcium (Ca) is in the same group as Barium (Ba) but is above it, so Ca has a higher ionization energy than Ba. Potassium (K) is in a different group, and its ionization energy is less than that of both Ca and Ba. Thus, the correct order is $Ca > Ba > K$.

Argon (Ar) is a noble gas with a completely filled valence shell, making it very stable and not inclined to gain any electrons. Thus, it has zero electron gain enthalpy. Lithium (Li), Calcium (Ca), and Fluorine (F) do not have zero electron gain enthalpy as they can gain electrons to achieve a stable configuration.

The element with atomic number 44 is Ruthenium (Ru), which belongs to the d-block of the periodic table. Elements in the d-block are also known as transition metals.