Question

Which is greater in size alkali metals or noble gases?

Answer 1

Answer:

Alkali metals are bigger in size than that of all noble gases.

Explanation:

the the reason why they are greater in size than noble gases is,

the atomic radius goes on decreasing from left to right and goes on increasing from top to bottom so as we go top to bottom in the group first they are the alkali metal group lithium will have the smallest size then sodium and calcium will have greater size than sodium and the last element of the group will have the largest radius and size in the whole periodic table as the noble gases are in the 18 group they have small radius but the radius is bigger than that of halogens all the halogens will have smaller radius than that of noble gases this is an exception.

Answer 2

Answer:

As we move along a period from left to right, the atomic radius of elements gradually decreases. This is because electrons are added in the same valence shell.

Consequently a proton is also increased in the nucleus of the atom. So the net effect is the size of the atom shrinks or the Atomic Radius of the element decreases. In period as we move left to right the atomic radius decreases.

So in a period the alkali metal will have the highest Atomic Radius and the Noble gas will have the lowest Atomic Radius.

The following data shows how the atomic radii in the period -2 gradually decreases as we from left to right.

Element ====>Atomic Radius (pm)

pm= pico- metre= 1 x 10^-12 m

Li =========> 167

Be =========> 112

B ==========> 87

C==========> 67

N==========> 56

O==========> 48

F ===========>42

Ne ==========> 38