Rank the following elements in order of decreasing atomic radius.

Question 1

Rank the following elements in order of decreasing atomic radius.

a. C

b. Sn

c. Ge

d. Si

Question 2

Rank the following elements in order of decreasing atomic radius.
Rank from largest to smallest radius. To rank items as equivalent, overlap them.
BR Cl I F

Rank the following elements in order of decreasing atomic radius.
Rank from largest to

Question 3

Arrange the following elements in order of decreasing atomic radius.

a. Al

b. Si

c. P

Answer to question 1

The elements C, Sn, Ge, and Si belongs to group 14 of the periodic table. The group 14 elements are referred to as the “carbon family”.

In a period, the atomic radius decreases whereas, in a group, it increases.

The atomic radius increases in a group due to an increase in the number of shells. The decreasing order is given as:

Sn<Ge<Si<CSn<Ge<Si<C

Thus, decreasing order of atomic radius is Sn<Ge<Si<CSn<Ge<Si<C.

Answer to question 2

Answer-

Atomic radius-It is the distance from the centre of the nucleus to the point up to which the density of the electron cloud is maximum.

Types of Atomic Radii :

Atomic radii are divided into 3 types: i) Covalent radius ii) Van der Waals radius iii) Metallic radius

Part-1 Decreasing order of atomic radius

I (5S25P5) >Br (4S24P5)> Cl (3S2 3P5) >F(2S22P5)

covalent radii- I (133 pm) >Br (114 pm )> Cl (99 pm) >F( 71 pm )

Ionic radii- I (220 pm) >Br (196 pm )> Cl (181 pm) >F( 133pm )

Reason-  As no of shell ( which increases with principal Quantam number) increases there is increase in atomic size.

Part-2   Decreasing order of atomic radius

Atomic size Na (191 pm)> Mg(160 pm ) > Al(130 pm )> Si (118 pm )

Reason- there is no change in no of shells these belong to same row, there is increase in no of electrons in the outermost shells so there is increase in coulombic force between outermost electrons to nucleous.

Answer to question 3

Aluminium (Al), silicon (Si), and phosphorous (P) belong to the same period, that is, the third period. Aluminium comes under the boron family, silicon is in the carbon family, and phosphorous is in the nitrogen family.

The electronic configuration of the given three elements is as follows:

  • Al13=[Ne]3s23p1Al13=[Ne]3s23p1
  • Si14=[Ne]3s23p2Si14=[Ne]3s23p2
  • P15=[Ne]3s23p3P15=[Ne]3s23p3

In the periodic table, the increase in atomic number is seen from aluminium to phosphorous. So, the nuclear charge of atoms also increases. An increase in nuclear charge causes a high attraction between valence electrons and the nucleus.

Due to the higher attraction, the atomic radius decreases from aluminium to phosphorous. So, the decreasing order of atomic radii is as follows:

Aluminium>Silicon>PhosphorousAluminium>Silicon>Phosphorous

Thus, the decreasing order is:

a>b>c

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