Question

name two elements of first period in Modern Periodic Table.

Answer 1

The answer is Hydrogen (H) and Helium (He).  

The elements of the first period in the Modern Periodic Table are the elements that occur in the first row of the same. These are hydrogen and helium.

Hydrogen is the lightest and the first element in the periodic table with an atomic number of 1. It plays a vital role in acid-base reactions.

Helium has an atomic number of 2 and is the first noble gas in the periodic table. It is also the second least reactive element and is chemically inert.

Answer 2

The answer to your question is "Hydrogen and Helium".

Hydrogen and Helium are the elements of the first period in the modern periodic table. Actually, the first period contains least elements as compared to any other row in the periodic table. All other periods contain at least 8 elements. 

The atomic numbers of hydrogen and helium are 1 and 2 respectively. Helium is also one of the inert elements found in nature.

Hope this will help.