How many of the following statements are correct?i) The 5th period of periodic table contains 18 elements. ii) Silicon, Germanium, Arsenic, Antimony, Selenium and Tellurium are semi metals.iii)  Si < Mg < Na order is correct for increasing metallic character.iv) Among Li−,Be−,B−  and C− , The ion Be−  is the least stable ion.v) Amphoteric oxide is feature of all metals.vi) The ionic radii of K+, Mg2+and Al3+  in A0 are 1.38, 0.72 and 0.535 respectively.vii) Second ionization energy of Copper is less than second ionisation energy of potassium.viii) The size of the isoelectronic species is also effected by charge on the ion.