Question

Why is it that hydrogen can be placed in both I A group and VII A group of the modern periodic table?

Short answer

Answer: Hydrogen can be placed in both Group 1 (IA) and Group 17 (VII A) of the modern periodic table due to its unique electronic configuration of 1s^1, which allows it to have similarities with both alkali metals and halogens. It can lose one electron to form H^+ like Group 1 elements or gain an electron to form H^- like Group 17 elements. Additionally, hydrogen is a non-metal, which aligns it more with the properties of halogens.

Step-by-step solution

Understanding the electronic configuration of hydrogen

The electronic configuration of hydrogen is 1s^1. It has only one electron in its outermost shell. This is the main reason why hydrogen can be placed in two different groups of the periodic table. Since it has only one electron, hydrogen can easily lose, gain, or share an electron, resulting in various possibilities.

Comparing hydrogen's properties with Group 1 (IA) elements

Group 1 elements, also known as alkali metals, have one electron in their outermost shell and typically lose one electron to form a +1 ion. Hydrogen shares similarities with these elements, as it also has one electron in its outermost shell and can lose one electron, forming H^+. Therefore, hydrogen is sometimes placed in Group 1 (IA).

Comparing hydrogen's properties with Group 17 (VII A) elements

Group 17 elements, also known as halogens, have seven electrons in their outermost shell and easily gain an electron to complete their valence shell, forming -1 ions (halides). Hydrogen, even though it has only one electron, can also gain an electron to complete its sole shell, forming H^-. This makes hydrogen similar to halogens in terms of electron gain, so it can also be placed in Group 17 (VII A).

Role of hydrogen as a non-metal element

Although hydrogen shares similarities with both Group 1 (IA) and Group 17 (VII A) elements, it's important to note that hydrogen is a non-metal. Hydrogen's non-metallic nature makes it more inclined towards the properties of halogens, as they too are non-metal elements.

Conclusion

In conclusion, hydrogen's electronic configuration of 1s^1 allows it to share properties with both Group 1 (IA) and Group 17 (VII A) elements in the modern periodic table. Hydrogen is able to lose, gain, or share an electron to form different ions, making it a unique element with versatile chemical properties.