In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomization of zinc is the lowest, i.e., 126 kJ mol−1. Why?

(c) Food cans are coated with tin and not with zinc because zinc is more reactive than tin.

Answer: We have 1 amu = 1.66 x 10-24 grams 126 amu = 126 x 1.66 x 10-24               = 209.16 x 10-24 grams 1 mole HNO3 = 63.01 g Hence 209.16 x 10-24 grams = 3.32 x 10-24 moles 1...

Ionization enthalpy is the energy required to remove an electron from an isolated gaseous atom in its ground state. Although the atoms are widely separated in the gaseous state, there...

Amount of energy required to dissociate one mole of bonds present between the atoms in gaseous molecules. As the molecules dissociate completely into atoms in the gaseous state, therefore bond...

[Hint : Due to smaller size of oxygen than sulphur electron-electron repulsion is more in oxygen than sulphur.]

(a) Due to lanthanide contraction, the size of           these elements is nearly same. (b) Transition metal contain large number of unpaired electrons, and they have strong interatomic attractions. (c)...

Stability of an ionic compound depends on its lattice energy. More the lattice energy of a compound, more stable it will be. Lattice energy is directly proportional to the charge carried...

(e) x + y = 23 and  xy = 126 Now x2 + y2 = (x + y)2 – 2xy (23)2 – 2 × 126 529 – 252 x2 + y2 = 277

(i) Because of large number of unpaired electrons in their atoms, the transition metals have strong interatomic interactions and hence stronger bonding between atoms, resulting in higher enthalpies of atomization. (ii)...

(a) The series is as follows: – 112, – 56, – 28, – 14, – 7 Hence, ? = 126 – 7 = 119