write the characterstics of s_block nd p_block elements
Answers
Answer:
PROPERTIES OF S-BLOCK ELEMENTS - DEFINITION
Following are the properties of s-Block elements:
They all are metals
They have low ionization enthalpies
They lose the outermost electron(s) to form cation
Group 1 elements lose 1 electron while the group 2 elements loses 2 electrons
Metallic character increases down the group
Because of high reactivity they are never found pure in nature
Reactivity increases down the group
Compounds of s-Block are ionic in nature
Exception to this is beryllium and lithium
PROPERTIES OF P-BLOCK ELEMENTS - DEFINITION
Following are the properties of p-block elements.
They are solids/liquids/gases at room temperature (Br is liquid)
They have variable oxidation states
They form acidic oxides
They impart no characteristic colour to the flame
Generally they form covalent compounds
Halogens form salts with alkali metals
They have high ionization potentials
They have very large electron gain enthalpies
The aqueous solutions their oxides are acidic in nature
Explanation:
Characteristics of s block elements
1.s block elements have spherical s orbital as their outermost orbital.
2.Since s orbital can accommodate a maximum of 2 electrons, each one of these elements have 1 or two electrons.
3.These s electrons are lost very easily to form monopositive ions by lsoing one electron in the outermost orbital or dipositive ions by losing 2 electrons.
4.They have low ionisation potentials and low electronegativities.
5.They are good conductors of heat and electricity, excepting H2 and He.
6.They are silvery, shiny metallic substances, (with the exception of hydrogen and helium which gaseous nonmetals).
7.They are malleable and ductile, i.e., we can make sheets and wires from them, (exception: H2, He).
8.They readily form ionic salts with most nonmetals.
9.Aqueous solutions of their oxides are alkaline.
10.They are listed in two columns at the left end of the Periodic Table, exception: He, which is at the right end.
11.The first column elements are called the alkline metals and the second column ones are called alkaline-earth metals.
12.The elements in s block are: Column 1: H, Li, Na, K, Rb, Cs and Fr. Column 2: Be, Mg, Ca, Sr, Ba and Ra. He is included in the last column.
Characteristics of p block elements
The four important characteristic properties of p-block elements are the following:
(a) p-Block elements include both metals and non-metals but the number of non-metals is much higher than that of metals. Further, the metallic character increases from top to bottom within a group and non-metallic character increases from left to right along a period in this block.
(b) Their ionization enthalpies are relatively higher as compared to s-block elements.
(c) They mostly form covalent compounds.
(d) Some of them show more than one (variable) oxidation states in their compounds. Their oxidizing character increases from left to right in a period and reducing character increases from top to bottom in a group.