Prediction of formula of stable binary compounds:
The formula of a stable binary compound is predicted using the valency or oxidation state of the combining elements so that electrical neutrality is achieved.
(a) Lithium and Oxygen
Lithium has valency +1 and oxygen has valency −2.
Stable compound formed:
Li2O
(b) Magnesium and Nitrogen
Magnesium has valency +2 and nitrogen has valency −3.
Stable compound formed:
Mg3N2
(c) Aluminium and Iodine
Aluminium has valency +3 and iodine has valency −1.
Stable compound formed:
AlI3
(d) Silicon and Oxygen
Silicon has valency +4 and oxygen has valency −2.
Stable compound formed:
SiO2
(e) Phosphorus and Fluorine
Phosphorus commonly shows valency +5 with fluorine.
Stable compound formed:
PF5
(f) Element 71 and Fluorine
Element with atomic number 71 is Lutetium (Lu). Lutetium shows a valency of +3 and fluorine has valency −1.
Stable compound formed:
LuF3
Final Answer (Summary):
(a) Li2O
(b) Mg3N2
(c) AlI3
(d) SiO2
(e) PF5
(f) LuF3
Given below are two statements:
Statement (I): According to the Law of Octaves, the elements were arranged in the increasing order of their atomic number.
Statement (II): Meyer observed a periodically repeated pattern upon plotting physical properties of certain elements against their respective atomic numbers.
In the light of the above statements, Choose the correct answer from the options given below:
The correct orders among the following are:
[A.] Atomic radius : \(B<Al<Ga<In<Tl\)
[B.] Electronegativity : \(Al<Ga<In<Tl<B\)
[C.] Density : \(Tl<In<Ga<Al<B\)
[D.] 1st Ionisation Energy :
In\(<Al<Ga<Tl<B\)
Choose the correct answer from the options given below :