Number of correct statements among the following are:

i) In ethene, molecular plane will be the nodal plane for $\pi -bond$
ii) In  $H_{2}C=CH-CH=C{H}_2$, all atoms are in same plane
iii)The amount of energy released when one mole of an ionic solid dissolved in water is called lattice energy. 
iv) With increase in percentage of s-character, electronegativity of hybrid orbitals increases.
v) Hybrid orbitals form strong bonds than pure orbitals
vi) Lithium ion $\left(L{i}^{+}\right)$  has more polarizing power than caesium ion $\left(C{s}^{+}\right)$.