What Group is Hydrogen in? And Why?

Hydrogen is in Group 1 (IA) of the periodic table. It is the first element in the periodic table, and it has only one electron in its orbit. ¹

Well, this was just a simple answer. But there are few more things to know about this topic which will make your concept super clear.

So let’s dive right into it.

Why is hydrogen in group 1?

Hydrogen is placed in group 1 of the periodic table because it has similar properties to the alkali metals in that group. Hydrogen has one electron in its outer shell, just like the alkali metals. ^{2 3}

This means that hydrogen can lose its electron easily to form a positive ion, just like the alkali metals. 

Hydrogen also reacts with other elements in similar ways to the alkali metals.
For example, hydrogen reacts with oxygen to form water, just like the alkali metals react with oxygen to form hydroxides. ^{4 5}

However, hydrogen also has some properties that are different from the alkali metals.
For example, hydrogen is a gas at room temperature, while the alkali metals are all solid metals. ^{6 7} Hydrogen is also less reactive than the alkali metals. ⁸

Overall, hydrogen is placed in group 1 of the periodic table because it has more similarities to the other elements in that group than it does to the elements in any other group.

Why is hydrogen not placed in group 17?

Hydrogen is not placed in group 17 of the periodic table because it does not have the same properties as the halogens in that group. 

The halogens are all non-metals that have a strong tendency to gain electrons to form negative ions. ⁹

Hydrogen, on the other hand, can either lose or gain electrons, depending on the reaction. ¹⁰

Here are some of the reasons why hydrogen is not placed in group 17:

• Hydrogen has a different electronegativity than the halogens. ¹¹ Electronegativity is a measure of how strongly an atom attracts electrons. Hydrogen has an electronegativity of 2.20, while the halogens have electronegativities of 3.00-4.00. ¹² This means that hydrogen is not as electronegative as the halogens and is not as likely to gain electrons.
• Hydrogen forms covalent bonds with other elements, while the halogens form ionic bonds. ¹³ Covalent bonds are formed when atoms share electrons, while ionic bonds are formed when one atom donates an electron to another atom. ¹⁴ Hydrogen is more likely to form covalent bonds than ionic bonds, which is another reason why it is not placed in group 17.

Overall, hydrogen has few properties that are similar to the halogens, but it also has major important differences. These differences are why hydrogen is not placed in group 17 of the periodic table.

Similarities and differences between hydrogen and group 1 elements

Here are some similarities and differences between hydrogen and group 1 elements:

Similarities

• Hydrogen has one electron in its outer shell, just like the alkali metals. ¹⁵
• Hydrogen can lose its electron easily to form a positive ion, just like the alkali metals.
• Hydrogen reacts with other elements in similar ways to the alkali metals. For example, hydrogen reacts with oxygen to form water, just like the alkali metals react with oxygen to form hydroxides. ¹⁶

Differences

• Hydrogen is a gas at room temperature, while the alkali metals are all metals.
• Hydrogen is less reactive than the alkali metals.
• Hydrogen has a higher ionization energy, while alkali metals have low ionization energy. ¹⁷

Overall, hydrogen is a unique element that has some properties that are similar to the alkali metals and some properties that are different. 

But as the majority of properties of hydrogen are like that of alkali metals, it is placed in group 1 of the periodic table.

Further reading

Why is Hydrogen in Group 1?
Is Hydrogen Reactive?
Why is Hydrogen Diatomic?
Is Hydrogen a Compound?
Why is Hydrogen Flammable?

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