Question

Please answer the following.

To. Arrange the following elements K. Cs. Sr. Ca, Ba and Li in order of increasing lonisation Energy 19. Arrange the following elements K, Cs, Sr, Ca, Ba and Li in order of increasing Radius Atomic size 20. Arrange the following elements K, Cs, Sr, Ca, Ba and Li in order of increasing Electronegativity 21. Arrange the following elements Rb, H, Be, Na, Cs and Ca in order of decreasing Radius Atomic size 22. Arrange the following elements Rb, H, Be, Na, Cs and Ca in order of decreasing Electron affinity

Answer 1

18)Ionisation energy decreases down the group and increases across the period

Consider Li,K,Cs these belong to Alkali group so it deceases down the group order is

Cs<K<Li

Consider Ca,Sr,Ba these also belong to Alkaline earth metal group next to Alkali so ionisation energy decreases down the group order is

Ba<Sr<Ca

Now consider Li,Ca,Sr,Ba in the period of Li we have Be next to lithium this beryllium consists of the group calcium strontium and barium so calcium and strontium has higher ionisation energy than Lithium but as barium is down the group it's size is more which has a tendency to lose electron so lithium has higher ionisation energy than barium so overall order is

Cs<K<Ba<Li<Sr<Ca

19)

Atomic radii decreases across the period and increases down the group

Consider Li,K and Cs (same group so increases)

Li<K<Cs

Consider Ca,Sr,Ba(same group so increases)

Ca<Sr<Ba

Consider K and Ca same period so deceases

Ca<K but Li<Ca

And also Sr<K

But

Ba>K and Ba<Cs

Order is

Li<Ca<Sr<K<Ba<Cs

20)

Electronegativity increases across the period and decreases down the group

So order is

Cs<K<Ba<Sr<Li<Ca

21)

Radius side increases down the group and decreases across the period

Consider H Na Rb Cs same group so increases

H<Na<Rb<Cs

Consider Be Ca same group so increases

Be<Ca

Overall order

H<Be<Na<Ca<Rb<Cs

22)

Electron affinity increases across the period and decreases down the group

Consider H Na Rb Cs

Cs<Rb<Na<H

Consider Be Ca

Ca <Be

Overall order is

Cs<Rb<Na<Ca<Be<H