As the radius of the atom increases down group 17 from top to bottom, and the valence shell electrons are increasingly shielded, the positively charged nucleus exerts less of an attractive force on the electrons so it has less ability to attract electrons towards itself, hence, electronegativity decreases down the group from top to bottom. Why is hydrogen in group 1 on the periodic table instead of a halogen in group 17? Covers the halogens in Group 17: fluorine (F), chlorine (Cl), bromine (Br) and iodine (I). With special reference to valency electrons & ion formation. Hydrogen - Hydrogen - Reactivity of hydrogen: One molecule of hydrogen dissociates into two atoms (H2 → 2H) when an energy equal to or greater than the dissociation energy (i.e., the amount of energy required to break the bond that holds together the atoms in the molecule) is supplied. In the coming lines we will discuss why hydrogen can not be placed in a particular group in the periodic table. Answer:Hydrogen's atomic number is 1,hence there is only 1 electron in outermost shell. Li , K , Na , K, Rb ,Cs and Fr of group 1 of the periodic table. between group 14,15, and 16 there is a patern between the boiling points with the boiling point being higher for the higher group- but group 17 dosn't fit the pattern it has lower boiling point then group 15 - why? The prime components of air, nitrogen and oxygen, are fourteen and sixteen times heavier, giving hydrogen dramatic buoyancy. Join now. They are called “halogens” because they give salts when they react with metals.So, now you know what halogens are! Thus it can lose an electron to achieve a stable configuration like alkali metals and hence can be placed in group 1 … Because Hydrogen only has 1 electron, it has 1 electron on it's outer shell. As well how do you explain the anomalies such as water? Li reacts with water to produce hydrogen gas. Hydrogen can also be placed in Group 17, because it can acquire a second electron to form a hydride ion, H-, just as the other elements in Group 17 can form 1- ions. In fact, they are the most reactive metals and, along with the elements in … Hydrogen can be in both group 1 and group 7 due to it's valence shell. They are very soft metals, which become liquid just above room temperature. So to be stable Hydrogen loses its electron and makes 1 positive charge. Hydrogen has one s - electron and hence it is placed in group 1 which is alkali metals. They aren’t that different. Like group I elements, hydrogen has only one electron in its valence shell. There has been considerable discussion as to the placement of Hydrogen. Ask your question. This time hydrogen (on the top) is being compared with kerosene (on the bottom, aviation fuel or JP-1). - Bromine is … 3) In some hydrogen differs from both alkali metals and halogens. Although hydrogen has an ns 1 electron configuration, its chemistry does not resemble that of the Group 1 metals . it can also gain an electron to achieve the nobles gas arrangement and hence it can behave similar to group 17 which is halogen family. Like halogens, hydrogen is a gas, and exists as a diatomic molecule (H2). It has 1 electron in its outer (only) shell, so it is placed above group one. Hydrogen is the chemical element with the symbol H and atomic number 1. Let us take a look at the similarities. please remember ther is some space between the group 1A and Hydrogen. This lightness of hydrogen made it a natural for one of its first practical uses - filling balloons. THESE PROPERTIES LEAD TO THE UNEXPLAINED POSITION OF HYDROGEN. For example, hydrogen reacts with halogens, oxygen, and sulphur to form compounds whose formulae are similar to those of alkali metals. Hydrogen can be placed in both group 1 and group 17 because its electronic configuration is similar to both the groups. Such that in the chart below comparing boiling points of groups 14-17 hydrides, the values of ammonia (NH 3), water (H 2 O), and hydrogen fluoride (HF) break the increasing boiling point trend. Position of hydrogen in the modern periodic table is controversial. All rights reserved. Properties of Hydrogen . Don’t worry, let us know and we will help you master it. it has le, IP in nucleus. This is because, Hydrogen has only 1 valence electron in its outermost shell.Like the Group I Alkali metals it has valency = 1 i.e it can lose electron. Why is hydrogen in 1. and in 17. group. Because hydrogen forms compounds with oxidation numbers of both +1 and -1, many periodic tables include this element in both Group IA (with Li, Na, K, Rb, Cs, and Fr) and Group VIIA (with F, Cl, Br, I, and At). That is why position of hydrogen is still undecided. He did so because hydrogen and alkali metals have similar properties. Lithium 1s 2 2s 1. Helium .. (2)electronegative character:-halogens have a strong tendency to gain one electron to form halide ions ..in a similar way hydrogen shows some tendency to gain one electron to form hydride ion .. H + e- -----> H(-) (He gas configuration), Cl + e -----> Cl(-) (Ar gas configuration). THESE PROPERTIES LEAD TO THE UNEXPLAINED POSITION OF HYDROGEN this is because it is often said that Hydrogen's place is unresolved in the table. In hydrides, hydrogen is bonded with a highly electronegative atom so their properties are more distinguished. It is metallic when frozen (like group 1) It can form alloys with metals (like group 1) Answer: Electronic configuration of hydrogen is 1 i.e. Like group I elements, hydrogen has only one electron in its valence shell. So its possible that hydrogen can … Sodium 1s 2 2s 2 2p 6 3s 1. IT IS JUST PLACED ABOVE group 1 of th table as it has valency one and cannot be placed with halogens as it has just one valence electron. VIEW SOLUTION. james harrington asked the Naked Scientists: Dear Dr. Chris, I'm a GCSE chemistry student (taking it through to AS and A level) and i've always been puzzled why hydrogen is in group 1 of the periodic table (with the alkali metals). The lightning test was inconclusive due to the container being obliterated in each case. 5 points marinescastro2 Asked 04/01/2020. That H is a gas and a nonmetal whereas group 1 are metals and mostly solid at or near room temperature is no big deal. but it is a special case so we shall place hydrogen at top of pereiodic table. Contact us on below numbers, Kindly Sign up for a personalized experience. State the electronic configuration of hydrogen [at. Hydrogen can be placed in both group 1 and group 17 because its electronic configuration is similar to both the groups. Explanation : H (Z=1): K 1. Let’s now look at the electronic configurationof these elements. For example, it forms stable/meta-stable peroxides/superoxides, like alkali metals, particularly potassium and beyond. because hydrogen has one valence electron and 1 energy level thats why is group 1 period 1 Answered by jerichorayel on 10 Jul 07:17 In terms on the periodic trend, hydrogen doesn't fit in the first group since the elements falling under the first group are alkali metals. Because hydrogen is so light, the pure element isn't commonly found on the Earth. The group 17 elements include fluorine(F), chlorine(Cl), bromine(Br), iodine(I) and astatine(At) from the top to the bottom. But some, like the one I was given, also show Hydrogen in the 7th group, to left of Helium. Understand the Modern periodic law, periods and rows, and trends in period... Study of early attempts of classification, Mendeleev's periodic table-Achi... Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day. This confirmed Kelly’s findings that the hydrogen fire ball dissipated quickly, providing less damage to the structure in every case versus the JP-1 test. With special reference to valency electrons & ion formation. It forms covalent compounds like halogens unlike alkali metals. +1.. (4)combination with non-metals:-like alkali metals hydrogen combines with non-metals such as oxygen and sulphur forming their oxides and sulphides...for example-- H2O, like Na2O ,K2O. Group 1A elements such as H, Li, K,etc. Explanation : H (Z=1): K 1. It burns when it comes into contact with oxygen. (5)Like alkali metals hydrogen also act as a strong reducing agent .. resempblence with halogens(Group -17 or Group VII)---. Resemblance with alkali metals It would just float away. Hydrogen also has only one electron. 1. (Therefor classed in group 1) Group 17 elements are also known as: (a) halogens (2) (name still in common use) (b) Group VIIA (name no longer used) Group 17 elements are non-metals; Group 17 elements exist as diatomic molecules (X 2) when not combined with other elements. (a) Halogen is a Greek word which means salt-former’. THESE PROPERTIES LEAD TO THE UNEXPLAINED POSITION OF HYDROGEN This is one of the factors that dictates the position of hydrogen in the table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. Hydrogen is a diatomic gaseous nonmetal, like most of the halogens. Similar to group 17, it will attract one electron to complete its shell. Hydrogen is the first element of the periodic table. Similarly, it can gain one electron to achieve stability.Like Group 17 elements,it can gain electron. Hydrogen can be placed in group 1[1A] as it forms a positive ion as in HC1 like alkali metals H. Question 2. Hydrogen is a chemical element with atomic number 1 which means there are 1 protons and 1 electrons in the atomic structure.The chemical symbol for Hydrogen is H. With a standard atomic weight of circa 1.008, hydrogen is the lightest element on the periodic table. Why is hydrogen placed in group one of the periodic table? Let us talk about hydrogen, a very interesting element, with an instructive video! Hydrogen shares many similarities with alkali metals, i.e. 1. Composed of a single proton and a single electron, hydrogen is the simplest and most abundant element in the universe. Let us take a look at the similarities. The alkali metals also react readily with water to produce hydrogen gas and metal hydroxides in the following video: Alkali Metals: Explosive reactions. ; Group 17 elements can combine with nearly all the elements in the periodic table. As it has only one electron, and the shell it occupies has a max of 2 it can either lose one electron or … Why is hydrogen placed in group 1 IA and group 17 VIIA ? Want a call from us give your mobile number below, For any content/service related issues please contact on this number. Log in. hi.. well hydrogen IS NOT in group 1 of the periodic table.. So its possible that hydrogen can … Hydrogen is very flammable and burns with an invisible flame. Hence, it can also be placed above the halogen group. Clean Energy Group raises concerns about harmful NOx emissions from new industry plans to burn hydrogen in fossil fuel power plants; calls for pause in permitting proposals until independent public health investigations are conducted -- particularly to study potentially dangerous air pollution impacts in environmental justice communities. Middle School. HOPE THIS HELPS ! 1) Electronic configuration : Like alkali metals, hydrogen also contains 1 electron in its outermost shell. Like halogens, hydrogen is a gas, and exists as a diatomic molecule (H2). document.write('This conversation is already closed by Expert'); Copyright © 2021 Applect Learning Systems Pvt. Indeed, some versions of the periodic table place hydrogen above fluorine in Group 17 because the addition of a single electron to a hydrogen atom completes its valence shell. Join now. ... Give the general group characteristic applied to hydrogen with respect to similarity in properties of hydrogen with halogens of group 17 [VIIA]. The group number determines how many electrons are on the outer shell of the atom. thus hydrogen like alkali metals exhibit electropositive character... (3).oxidation state :-like alkali metals hydrogen exhibits an oxidation state of +1 in its compounds... for example- HCl ,, NaCl ,, KBr ...here oxidation state of H is same as Na and K i.e. Although astatine is radioactive and only has short-lived isotopes, it behaves similar to iodine and is often included in the halogen group. (b) This is because halogens are reactive non-metals. Hydrogen is the raw fuel that most stars 'burn' to produce energy. It is normally gaseous and diatomic (H2), like group 17. He positioned hydrogen in the first column above alkali metals. With a standard atomic weight of 1.008, hydrogen is the lightest element in the periodic table.Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass. Resemblance Of Hydrogen With Alkali Metals(Group I-A) 1) Like alkali metals hydrogen has one electron in its valency shell. A conceptual question: In Chemistry, Hydrogen has always been regarded as an "outlier" of sorts--exhibiting the characteristics of family 1 elements yet only have one valence electron filling the 1s orbital. Hydrogen is considered as a very unique element.The position of this small element in the periodic table is debatable. Most periodic tables only feature one Hydrogen atom, on the top of the first group. Physical and Chemical Properties of Group 17 Elements Group 17 Elements: The Halogens The elements in Group 17 are: Fluorine Chlorine Bromine Iodine Astatine These elements are known as halogens. have 1 valency. The two hydrogens are the same, but some periodic tables show hydrogen in both places to emphasize that hydrogen isn't really a member of the first group or the seventh group. Hydrogen also resembles halogens in many ways. elements in group I-A. ! Like group I elements, hydrogen has only one electron in its valence shell. But it is not a halogen either. The byproduct of a hydrogen and oxygen explosion is water or H 2 O. Hydrogen gas is made up of diatomic molecules designated as H 2. Hydrogen can be placed in both group 1 and group 17 because its electronic configuration is similar to both the groups. In the coming lines we will discuss why hydrogen can not be placed in a particular group in the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. This means that they are less capable of donating an electron, and want to keep them because their electron orbital becomes fuller. 1].e Give a reason why hydrogen can be placed in group 1 [1A] and group 17 [VIIA] of the periodic table. state 3 reasons why hydrogen can be placed in group 1 or group 17 - Chemistry - TopperLearning.com | 47lxjtll Hydrogen was first recognized as a distinct element by Henry Cavendish in 1766. 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