Question

Which of the following statements concerning lattice energy is false? It is often defined as the energy released when an ionic compound forms from its ions. MgO has a higher lattice energy than NaF. In the Lewis structure for elemental nitrogen, there is (are) a single bond between the nitrogen atoms a double bond between the nitrogen atoms a triple bond between the nitrogen atoms three unpaired electrons two unpaired electrons, one on each nitrogen What is the geometry of PH_2? An element has an electronic configuration of [Kr]5s^2 4d^10 5p^2 The element is a(n) What is the electronic configuration for yttrium?

Answer 1

1. All of the above statements for lattice energy are correct except option ‘c’.

2. Lewis structure for N2 is as follows,

Nitrogen has 5 valence electrons, the 3 electrons from each will form a triple bond, leaving a remaining lone pair on each Nitrogen, :N≡N:

3. PH3 molecule has the central f phosphorus atom connected via single bonds to three hydrogen atoms. The phosphorus atom also has one pair of unshared electrons. The electron-cloud geometry of the phosphorus atom is tetrahedral, but the PH3 molecular geometry is trigonal pyramidal.

4. Given that electronic configuration of element is [Kr]5s24d105p2. If we calculate atomic number by writing down whole configuration atomic number comes to 50, therefore it is Sn metal(Tin). It cannot be a transition metal because d orbital is completely filled and also it is not from lanthanide and actinide groups as those elements are heavy, large and more d and e orbitals.

Additionally it cannot be a non-metal as well because they are small and have very less d and p orbitals. Hence we can conclude that it is a meta

5. Electronic configuration of yettrium (Y) is Kr 4d1 5s2 with atomic number 39. It is chemically similar to lanthanides and also classified as rare earth element.