Single Choice

The low density of alkali metals is due to

Atheir BCC structure in which about $$32$$% of the available space is unfilled
Correct Answer
Btheir HCP structure in which about $$74$$% of the available space is unfilled
Ctheir cubic close packed (CCP) structure in which about $$74$$% of the available space is unfilled
Dtheir BCC structure in which about $$47$$% of the available space is unfilled

Solution

Alkali metals are elements in Group 1 of the periodic table and are very reactive in water.

This the reason why they are not denser.

Alkali metals have very high reactivity, so the smaller the ionization energy count the more reactive it gets, Alkali metals have the smallest ionization energy being in Group 1 which is why they have low density. Even they (the alkali metals) should not be exposed to oxygen at all or they will easily react.



solution



Percentage of free space in a body centered cubic unit cell is 32%.

Percentage of occupied space in a body centered cubic unit cell is 68%.

Alkali metals have low density because of their large atomic size. They have only one valence electron. As a result, their metallic bonding is weak. They are, therefore, soft metals of low density.

Hence , option A is correct.

SIMILAR QUESTIONS

Solid State

Number of atoms per unit cell in B.C.C. is:

Solid State

If a is the edge length, In BCC, the distance between two nearest atoms will be:

Solid State

CsBr crystallizes in a body-centered cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 and that of Br = 80 amu and Avogadro number being $$6.02\times 10^{23}$$ mol$$^{-1}$$, the density of CsBr is:

Solid State

The radius of the largest sphere which fits properly at the centre of the edge of body centred cubic unit cell is:(Edge length is represented by '$$a$$')

Solid State

An element has a body centered cubic (bcc) structure with a cell edge of $$288 pm$$. The atomic radius is

Solid State

Body centred cubic lattice has a co-ordination number of:

Solid State

The intermetallic compound $$LiAg$$ crystallizes in a cubic lattice in which both $$Li$$ and $$Ag$$ atoms have coordination numbers of $$8$$. To what crystal class does the unit cell belong?

Solid State

What is the theoretical density of crystalline $$K$$?

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