a) Which element will form a divalent cation?
b) Write the formula of the compound formed by the reaction between A and D.
c) How many bonds are present in the molecule R2.?Name the type of bond present in this
molecule ?
Answers
Answer:from this question c will show divalent catinatin
Explanation:
Please Note - The missing table in the question has been attached below.
SOLUTION :
(A) The element 'B' will form a divalent cation.
(B) The formula of the compound formed by the reaction between 'A' and 'D' is A₂D.
(C) There are three bonds present in the molecule R₂, which are covalent in nature.
(A) A divalent cation is of the form M²+, where M is a metal.
• Now, according to the periodic trend, the elements belonging to group I and group II in the periodic table are highly metallic in nature, and their valency is equal to their respective group numbers.
• So, the element 'B' belonging to group 2 in the periodic table will have a valency of +2, forming a divalent cation.
(B) A bond is formed by the transfer or sharing of valence electrons between two elements to attain octet in each of them.
• Element 'A' belongs to group 1 in the periodic table. So, it has 1 electron in its valence shell.
• For element A, it is easier to lose its 1 valence electron to attain stability rather than gaining 7 more electrons to attain octet.
• The element 'D' belongs to group 16 the periodic table. So, the number of electrons in its valence shell is equal to 16 - 10 = 6.
• For element D, it is easier to gain 2 electrons to complete its octet rather than losing all 6 of its valence electrons for attaining the same.
• Therefore, when 'A' and 'D' are reacted, A readily loses its 1 extra electron, which is gained by 'D'.
• Now, D needs 2 e- in total to attain octet. Therefore, 'D' reacts with two atoms of 'A', forming a compound of the formula A₂D.
(C) The element 'R' belongs to group 15 in the periodic table. So, its number of valence electrons is 15 - 10 = 5.
• An element with 5 valence electrons can neither gain nor lose electrons. It can only share its valence electrons.
• In order to be stable, each R atom needs to acquire 3 more electrons in its valence shell to complete its octet.
• So, two atoms of R share 3 valence electrons each with one another, so that they both have 5 + 3 = 8 electrons in their valence shell. This results in the formation of an R₂ molecule.
• Since three electrons are shared by each atom of R, three bonds are present in the R₂ molecule.
• A bond which is formed by the sharing of electrons is called a covalent bond. Therefore, the bond in R₂ molecule is covalent in nature.
