Dealing with trends of chemistry:
The periodic table is a table or chart of Chemistry containing elements found in nature used in every chemistry part. There you get information regarding every element such as shape, atomic number, m.p, b.p, etc.
In chemistry, we find lots of increasing and decreasing trends, and some include as an exception. Some of these are listed below GroupWise.
Classification Of elements of the periodic table
Elements found in nature are placed in a periodic table according to their similarity with other metals.
So based on the chemical properties and physical properties, Our basic science makes a classification of elements placed in the periodic table.
Fig-1: periodic table of elements
The periodic table contains 18 groups and 7 Periods. It is a collection of different elements. These elements are basically classified into three types
1. Metals, 2. Metalloids 3. Nonmetals
A) Metals:
Metals have a specific name of category like
a) Alkali metals, b) Alkaline Earth metals, C) Inner transition metal (Actinides and Lanthanides), d) Transition metals
B) Metalloids:
It is the intermediate portion of metal and non-metal. They are known for showing both types of behavior; they act as metals and non-metals.
C) Nonmetals
Nonmetals C, N, O, P, S, Se, Halogens and noble gases.
Here, majority of trends of periodic table are made of Gr-1,2,13,14,15,16,17 & 18. But Only trends of Gr- 1, 13,14 & 15 are mentioned here.
Our page will update and include other groups' trends, So follow it and read it.
Groupwise trends
A) Group-1:
Group -1 contains H, Li, Na , K ,Rb ,Cs and Fr. Li to Fr are known as "Alkali Metals' .Lots of trends on different chemical properties and physical properties are observed for them . These trends are listed by numbering below:
1 .Meltingpoint:
Li >Na > K > Rb > Cs
2.Colour of flame:
Metal(s). Colour of flame
i. ) Li. Red
ii.) Na. Golden
iii.)K violet
iv.) Rb Red
V.) Cs Blue
3.Stability of Hydride:
LiH >NaH >KH >RbH >CsH
04.Basic nature of hydroxides:
LiOH < NaOH< KOH < RbOH
05.Hydration Energy:
LI> Na> K>Rb >Cs
06. Reducing character:
Li >Cs >Rb >K >Na
B) Group -2:
Group-13 contains B (Metalloid), Al, Ga, ln, Tl. They show a lot of trends in different chemical properties and physical properties. Some of these are listed or pointed below by numbering:
1. Stability order of (+3) oxidation state:
B >Al> Ga>In >Tl
2. Stability order of (+1) oxidation state:
Ga < In < Tl
3.Order of Basic nature of the oxides and hydroxides:
B< Al < Ga < ln < Tl
4. Order of Ionisation energy (remember must)
B > Al< Ga> ln>Tl
C)Group -14:
Group -14 contain C, Si, Ge , Sn, Pb . Among these elements , Si and Ge are considered as " Metalloid" . They show lot of trends or order on different chemical properties and physical properties performed by them .Some of these are listed below by numbering:
1.order of metallic character:(gr-14)
C < Si < Ge < Sn < Pb
2.Order of acidic character of oxides:
CO2 >SiO2 >GeO2 >SnO2 >PbO2
3.order of reducing nature of hydrides:(important)
CH4 < SiH4 < GeH4 < SnH4 < PbH4
4. Order of thermal stability of tetrahalides:
CCl4>SiCl4 > GeCl4 >SnCl4 > PbCl4
5.Order of oxidising power of M+4 species:
GeCl4 < SnCl4 < PbCl4
6.Ease of hydrolysis of tetrahalide:
SiCl4
D)Group-15:
Group -15 contains N, P, As, Sb and Bi. Among the group, -15 elements, As (Arsenic) and Sb ( antimony) are considered as "metalloid." These group elements show different trends or orders of different chemical properties and physical properties (Significant for exam purpose. So, keep in mind always). These are listed below by number:
1.Acidic trends of trioxides:
N2O3 >P2O3 >As2O3
2.Acidic strength of pentoxides:
N2O2 >P2O2 >As2O2 >Sb2O2 >Bi2O2
3. Acidic strength of oxides of nitrogen (very, very important for competitive exams purpose)
N2O5 > N2O4 > N2O3 >NO >N2O
4.Basic nature /Bond angle /Thermal stability and dipole moment of hydrides:
NH3 > PH3 > AsH3 >SbH3 >BH3
5.Stability of trihalides of Nitrogen:
NF3 > NCl3 > NBr3
6.Lewis's base strength:
NF3 < NCl3 < NBr3 < NI3
7. Lewis's acid strength of trihalides of P, As, and Sb:
PCl3 > AsCl3 > SbCl3
8. Lewis's acid strength among 'P' trihalides:
PF3 > PCl3 > PBr3 > PI3
Reference used:
1. Inorganic chemistry by House croft.
2. Principle of inorganic structure and reactivity by James Hurry Keiter.
3.Chemical sciences (UGC CSIR NET /SET, IIT -GATE) by Dipendu Patra and Subrata Sengupta.
4.Principles of inorganic chemistry by puri, Sharma, Kalia.
5. IIT JAM CHEMISTRY by Arihant publication.
6. IIT -Jee main and advanced Solved paper by Ranjeet Shahi, Arihant publication.
7. Advanced inorganic chemistry by
Satya Prakash, Dr.G.D Tuli , Dr. S .k .Basu. Dr. R.D Ramadan.
Conclusion:
This article has been made by reading lots of books and competitive exam questions papers. So, this increasing and decreasing order of elements having different groups and periods of the periodic table is important for students' exam purpose.
It helps students a lot as many trends are found in chemistry, this collection will easier the study of students. Try to keep in mind these trends always as it saves students' time in exams to perform lots of questions with the given time. Could you read it and enjoy chemistry?
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