Question

Which of the following is the lightest metal?
A. Mercury
B. Silver
C. Lithium
D. Lead

Answer 1

Hint: Lightness of the metal depends on its atomic weight. Atomic weight of any substance or element is calculated by adding the total mass of all the elements present.

Complete step by step answer:
> Mercury belongs to the 12th group and 6th period. It has symbol as Hg and its atomic weight is 80.It has isotopes as \[^{202}\text{Hg}\] and$^{204}\text{Hg}$ with mass of 200.59 u.
> Silver is located in group 11 and period 5.It has a symbol as Ag and its atomic number is 47. Atomic weight of silver is 107.868 u.
> Lithium belongs to the 2nd period and group 1 of periodic table. it's atomic number is 3 and atomic weight is 6.941 u.
> Lead belongs to the 14th group and 6th period. It's atomic number is 82.It has a symbol as Pb and its atomic weight is 207.2 u.
So from all above, the lightest metal is Lithium with atomic weight as 6.941 u, therefore option C is correct.

Additional information:
- Mercury is commonly known as quicksilver and was formerly known as hydrargyrum. It is a d-block element that is liquid at standard conditions for temperature and pressure.
- Silver is transition element which belongs to d-block ,the main isotopes of silver are:$^{105}\text{Ag}{{\text{ }}^{106\text{m}}}\text{Ag}{{\text{ }}^{107}}\text{Ag}{{\text{ }}^{108\text{m}}}\text{Ag}{{\text{ }}^{109}}\text{Ag}{{\text{ }}^{110\text{m}}}\text{Ag}{{\text{ }}^{111}}\text{Ag}.$
- Lithium element is commonly used to treat bipolar disorder and treat major depressive disorders.
- Lead is a relatively unreactive post-transition metal. It is amphoteric in nature and it generally forms covalent bonds.
Note: Don't confuse yourself with the lightest metal and non-metal. Sometimes in question it is asked for lightest metal and sometimes lightest non-metal, beware and then answer.