Question

Given below are the names of mass of few elements based on their position in the periodic table. Identify the element which is not correctly placed.
A. An element which tends to lose three electrons – Aluminium.
B. An element which tends to gain two electrons – Iodine.
C. An element with valency four – Silicon.
D. A transuranium element – Plutonium.

Answer 1

Hint: Periodic table helps to predict the position and nature of an element. The group and periods of a particular element reflects its chemical and physical properties.

Complete answer:
Let us discuss it one by one:
(A) Aluminium: It belongs to the p – block element. Atomic number of aluminium is 13. The ground state electronic configuration of Al is,
Al = $1{s^2}2{s^2}2{p^6}3{s^2}3{p^1}$
According to its electronic configuration it can lose up to 3 electrons to form a tripositive $A{l^{3 + }}$ cation.
$Al\xrightarrow{{}}A{l^{3 + }} + 3{e^ - }$
$Al$ can form covalent bonds as well.
So, the property of aluminium is matching with the statement.
(B) Iodine: Iodine element belongs to the group – ${17^{th}}$ in the periodic table iodine can gain only one electron or it can share up to 7 electrons.
\[I + 1{e^ - }\xrightarrow{{}}{I^ - }\]
Because iodine has seven valence electrons. It will complete its octet when it gains one electron.
Iodine cannot gain 2 electrons so its property is mismatched.
Iodine can also form interhalogen compounds.
(C) In the case of silicon, it belongs to the group – ${14^{th}}$ in the periodic table. It has four valence electrons in the outermost shell. It shares four valence electrons with other atoms to complete its octet
(D) Plutonium: It comes after uranium and has a higher atomic number than uranium, so it is a transuranic compound.
Its property is also properly matched.

So the incorrect option is (B).

Note: The periodic table provides a systematic framework for organizing the large available information on the chemical behaviour of the elements into simple logical patterns. Using the position of an element in the periodic table, it is possible to predict its chemical behaviour. Plutonium belongs to the actinides series. Atomic number of this element is 94. Transuranic elements are the chemical elements with atomic number greater than 92, which is the atomic number of uranium. The atomic number of plutonium is greater than uranium i.e.94, so the plutonium element is known as transuranic element.