Question

Is Lithium metal dangerous?

Answer 1

Lithium is a metal found in the 1st group (s-block) of the periodic table. Its atomic number is 3 which means its electronic configuration is $1{s^2}2{s^1}$. We find that this configuration means that the $2s$ orbital can easily lose the electron to form a stable configuration. Lithium appears to be a pretty, shiny silvery metal but doesn’t stay that way for long because of its reactivity.

Complete answer:
Lithium metal due to its electronic configuration always tends to lose 1 electron and form a stable $1{s^2}$ configuration. Due to this they react very vigorously. When lithium comes in contact with air they spontaneously ignite. This is a potential fire hazard and therefore poses serious issues of storage. Lithium should be stored under argon and in containers free of moisture and ample air supply.
They can also fume when heated, producing toxic fumes that when inhaled can cause a wide range of health hazards.
When lithium comes in contact with moisture or water they become corrosive
Exposure to lithium can cause loss of appetite, nausea, headaches, burning sensation, redness, pain, muscle weakness, seizure and even coma in some cases.
Inhaling Lithium vapours can irritate the lungs. When the exposure is prolonged this can cause fluid build-up in the lungs causing pulmonary edema which is a medical emergency.
So in conclusion we can say that Lithium is a very dangerous metal.

Note:
Always see the electronic configuration of the element under question when these types of questions are asked. If the metal has a chance to form stable configuration by the loss of a couple of electrons (energy efficient way) they are always very reactive.
E.g. Sodium (also an alkali metal) is very reactive and can vigorously react with water and is stored under kerosene. Its electronic configuration is $1{s^2}2{s^2}2{p^6}3{s^1}$
In case of non-metals they are highly reactive as they can form stable electronic configuration by gaining electrons.