Question

Atomic size of nickel, cobalt and iron is in order of $Fe > Co > Ni$ .
A. True
B. False

Answer 1

Atomic size is basically the distance between the center of the nucleus of an atom and its outermost shell. It is the shortest distance between the atom’s nuclei and the outermost shell of the atom. Moreover, atomic radius decreases as we move from left to right in a period and increases as we go down the group.

Complete step by step answer:

The modern periodic table is based on the law that the properties of an element are aperiodic functions of their atomic number. Further, these properties are related to the electronic configuration of the elements. We observe a common trend in the properties as we move across a period or down the group and these properties are further known as periodic properties. Some of these properties are atomic size,metallic character, non-metallic character, electronegativity etc. Now let’s discuss the atomic size trends. As we know that the distance between the center of the nucleus and the outermost shell of an atom is known as the atomic radius. Now, in a group, the atomic size increases due to the addition of shells as we move from one period to another but it further decreases across a period because the number of shells remains the same while the nuclear charge increases. This further leads to the pulling of electrons from the outermost shell towards the nucleus and thus decreasing the size. Now, as we know that as we move along a period, the radius decreases but in d block they have almost the same radius or we can say that they have approximately equal size. So, in case of Fe, Co and Ni the atomic radius remains the same.

Hence, the given statement is false.

Note: Iron, a transition metal is widely used in the construction industry. It is usually alloyed into steel which exhibits greater tensile strength and versatility. Another transition metal i.e. Ni is used in the production of stainless steel. Moreover, copper is widely used in electrical wiring because of its high tensile strength, malleability, ductility and electrical conductivity.