Question

Which of the following is the lightest metallic element?
a.) Mg
b.) Al
c.) Li
d.) Mn

Answer 1

Hint: All those elements which have a tendency to electrons are known as metals. Solve this question by comparing the given elements on some basic properties such as their atomic number and atomic weight. The element with a lesser number of shells will be lighter.

Complete step by step answer:
The elements given in the options are –
Lithium –
Atomic number = 3
Atomic weight = 6.9 u
Magnesium
Atomic number = 12
Atomic weight = 24.305 u
Aluminium
Atomic number = 13
Atomic weight = 26.98 u
Manganese
Atomic number = 25
Atomic weight = 55 u
We arrange the elements either on the weights or atomic number as – Li < Mg < Al < Mn
Therefore, the answer is – option (c) – Lithium is the lightest metallic element amongst the given options.

Additional Information:
Most elements in the periodic table are metals – alkali metals, alkali earth metals, transition metals, actinides and lanthanides.

Note: All metals have the following properties –
They generally have less than four electrons in their valence shell
All metals are hard (except – Sodium and potassium)
Metals are generally solids at room temperature (except – mercury)
Metals are malleable, lustrous, ductile
They are good conductors of electricity and heat (silver and copper are the best conductors)
They have low ionization energy
They have low electronegativity
They act as reducing agents.