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Position of Hydrogen in Periodic Table

Last Updated : 29 Feb, 2024
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Hydrogen is a chemical element with the symbol H and the atomic number 1 and a mass of 1.008amu on average. Lavoisier termed this gas Hydrogen in 1783. The term comes from the Greek words “hydro” and “genes,” which both indicate “water producer.” In the year 1672, Robert Boyle was the first scientist to create this gas. In the year 1766, Henry Cavendish investigated its qualities.

To begin, we can argue that hydrogen is the lightest atom because it only contains one electron. Furthermore, the loss of this electron results in the proton, an elementary particle. Furthermore, hydrogen has a one-of-a-kind distinctive attribute. Furthermore, there are three isotopes of hydrogen: deuterium, protium, and tritium. Only tritium is radioactive among these three isotopes. On the other hand, it has properties that are similar to both halogens and alkali metals. 

The fact that it has its own spot in the periodic table due to its unique features is notable. It also cannot be found in its natural state in the earth’s atmosphere. The water-gas shift reaction from petrochemicals is used to produce dihydrogen on an industrial scale. Furthermore, the H-H bond of dihydrogen has the highest dissociation enthalpy of any single bond between two atoms of any element. Furthermore, a hydrogen torch, which is good for welding, uses this feature. In addition, dihydrogen’s reducing process produces methanol, hydrogen halides, ammonia, water, and other products. Furthermore, the electrolytic enrichment of normal water produces heavy water, which is an essential chemical.

What is Hydrogen’s Position in the Periodic Table?

Because hydrogen has an atomic number of one, it has only one electron in its atom and consequently only one electron in its outermost shell, making it the first element in the periodic table. The electrical configuration of elements determines their placement in the periodic table.

This structure resembles alkali metals (ns1), which have one electron in their outermost shell. By admitting one electron, it can achieve the noble gas configuration of helium. This property is quite similar to that of the halogen family (ns2 np5), which is similarly missing one electron to complete the octet of electrons in its shell. Hydrogen resembles alkali metals when it loses an electron and forms a cation, but when it acquires an electron and becomes a uni-negative ion, it resembles halogens.

The place of hydrogen in the periodic table was a huge question based on these qualities.

Hydrogen in the Periodic Table

In terms of compound formation, hydrogen produces oxides, halides, and sulfides that are similar to alkali metals, but it has a far higher ionization enthalpy, hence it lacks metallic characteristics under normal conditions. Hydrogen is found to be more similar to halogens than alkali metals in terms of ionization enthalpy.

Lithium, for example, has an iH of 520 kJ mol-1, fluorine has an iH of 1680 kJ mol-1, and hydrogen has an iH of 1312 kJ mol-1. When the H2 molecule is produced, it exists as a diatomic molecule similar to that of halogens (for example, chlorine Cl2), with a single hydrogen bond.

Despite its similarities to halogens and alkali metals, hydrogen is quite distinct from both. As a result, the position of hydrogen in the periodic table must be carefully considered. When hydrogen loses an electron, the size of its nucleus shrinks to around 1.5 x 10-3 pm, which is extremely small relative to the atomic sizes of normal metals, and hence hydrogen ion does not exist freely in nature.

Resemblance with Halogens

  • Electronic Configuration – Halogen atoms have seven electrons in their valence shells, and just one electron is required to achieve a stable configuration akin to noble gases. Similarly, one electron is required for the hydrogen atom to achieve a stable state.
  • Atomicity – All halogen molecules, including hydrogen, are diatomic. As an example, H2,F2,Cl2,Br2,I2, etc.
  • Formation of Mono-negative Ions – By gaining an electron, hydrogen, like halogens, can form a mono-negative ion.

H + e–  → H

F + e→ F

Cl + e→ Cl

  •  Ionisation Energy –
Element H F Cl Br

Ionization energy 


1310 1681 1255 1121
  • Non-metallic Nature – Hydrogen is a non-metal that conducts heat and electricity poorly, similar to halogens.
  • Liberation at the Anode During Electrolysis – Hydrogen gas is liberated at the anode when compounds like LiH, NaH, CaH2, and others are electrolyzed in the molten state, just as halogens are liberated at the anode when compounds like NaCl, PbBr2 are electrolyzed.
  • Oxidation State – Hydrogen, like halogens, can have a –1 state in some of its compounds.
  • Combination with Metals – Hydrogen, like halogens, reacts with non-metals such as C, Si, Ge, and other non-metals to produce covalent compounds.

As a result, hydrogen resembles alkali metals (group 1) on the one hand and halogens (group 17) on the other. As a result, it appears that hydrogen should be placed in both group 1 and group 17 at the same time. However, there are certain differences between hydrogen and alkali metals and halogens. Hydrogen varies from alkali metals and halogens in various ways.

Dissimilarities of Hydrogen with Alkali Metals and Halogens

  • Alkali metals and halogens contain several shells, but hydrogen atoms only have one.
  • Alkali metal oxides are basic in nature, halogen oxides are acidic in nature, and hydrogen oxides are neutral in nature.
  • A hydrogen atom can lose, gain, and even share electrons during the production of its compounds due to its unusual electrical structure. Alkali metals and halogens both lack this distinctive property.

As a result, determining the exact place of hydrogen in the periodic table is rather challenging.

Uses of Hydrogen

Because of its dual nature, hydrogen has a wide range of applications. The following are some of the most important applications for hydrogen:

  • Hydrogen is employed in the production of nitrogenous fertilizers and the synthesis of ammonia.
  • Vanaspati fat is made by hydrogenating unsaturated vegetable oils.
  • It’s used to make a variety of organic chemicals, including methanol.
  • Hydrogen chloride is a chemical that can be made from hydrogen.
  • Metallurgical operations can convert several metal oxides to metals using hydrogen.
  • Many space research projects employ hydrogen as rocket fuel.
  • Hydrogen fuel cells are being used in the automotive sector to test hydrogen fuel.

Sample Questions

Question 1: What makes hydrogen so unique?


The simplest and most abundant element in the universe is hydrogen. It is made up of only one proton and one electron. When mixed with liquid oxygen, liquid hydrogen is employed in the study of superconductors and produces a great rocket fuel. Hydrogen combines with other elements to generate a variety of compounds.

Question 2: Is hydrogen gas or metal?


Hydrogen is frequently categorized as non-metal since it possesses numerous non-metal properties. This is, for example, a gas at room temperature. Hydrogen, on the other hand, shares characteristics with alkaline metals in group 1. In the liquid state, hydrogen conducts electricity precisely like a metal.

Question 3: Where is hydrogen commonly used?


In the glass industry, hydrogen is employed as a protective environment for making flat glass sheets. In the electronics industry, it is utilized as a cleansing gas during the fabrication of silicon devices. Because of its low density, hydrogen was an obvious choice for one of its initial applications: inflating balloons and airships.

Question 4: What are the physical characteristics of hydrogen?


Physical Properties of Hydrogen are as follows:-

  • It is thinner than air with vapor density.
  • It is thinner than air with a vapor density of 1.
  • Is is non-poisonous gas.

Question 5: Why is hydrogen’s place in the periodic table a point of contention?


Because of its similarities to alkali metals and halogens, hydrogen’s location in the periodic table is debatable.

Question 6: What is hydrogen’s place in the periodic table based on its electronic configuration?


Hydrogen, commonly known as protium, is the first element in the periodic table. It has an [1s1] electrical arrangement. Hydrogen, like alkali metals and halogens, has a dual behavior due to the presence of only one electron. As a result, it is positioned above the alkali metals in group 1 and alongside the halogens in group 17.

Question 7: Why is hydrogen so important?


The most crucial hydrogen function in the human body is to keep you hydrated. The body’s cells absorb water, which is made up of hydrogen and oxygen. As a result, it is a critical element that is employed as fuel, military weaponry, and other applications, but not in human bodies.

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