Question

What were the first three elements?

Answer 1

• The periodic table consists of $118$ elements that are known to us.
• Initially, in the time of the Big band theory more than 14 billion years ago, the three known elements were Hydrogen, Helium, and Lithium.
• The atomic number and mass number of Hydrogen$\left(\mathrm{H}\right)$ are $1\mathrm{and}1$respectively.
• The atomic number and mass number of Helium$\left(\mathrm{He}\right)$ are $2\mathrm{and}4$are respectively.
• The atomic number and mass number of Lithium$\left(\mathrm{Li}\right)$ are $3\mathrm{and}7$are respectively.

Hence, the first three elements were Hydrogen, Helium, and Lithium.