Position of hydrogen in periodic table
Position of an element in Periodic Table depends upon its electronic configuration and properties. Hydrogen resembles the elements of group I-A, IV-A and VII-A in some respects. Properties of hydrogen do not completely match any one of the above-mentioned groups. That is why position of hydrogen is still undecided.
Resemblance Of Hydrogen With Alkali Metals(Group I-A)
1) Like alkali metals hydrogen has one electron in its valence shell.
Explanation
H (Z=1): K1
Li (Z=3): K2, L1
Na (Z=11): K2, L8, M1
(2) Both require just one electron to complete their valence shells.
3) Both hydrogen an alkali metals are good reducing agents.
4) Like alkali metals hydrogen can also form halides.
Explanation: Hydrogen:
HCl, HI.
I-A:
NaCl, KBr.
5) Halides of alkali metals and hydrogen ionized in similar way in aqueous solution.
Explanation:
HCl (aq) è H+(aq) + Cl-(aq)
NaCl(aq) è Na+(aq) + Cl-(aq)
6) Like alkali metals hydrogen can also form compounds with non-metals.
Explanation:
I-A:
Na2S
Hydrogen:
H2S
7) Both lose electron to form positive ions. E.g. H+, Na+
8) Alkali metals and hydrogen belongs to s block.
DIFFERENCES :-
1) Hydrogen is a non-metal where as elements of I-A are metals.
2) Hydrogen can form both covalent and ionic compounds. But alkali metals only form ionic compounds.
3) Hydrogen can gain an electron to form H- ion.
4) Hydrogen is a gas at room temperature but alkali metals are solids.
5) Unlike Na+ or K+ hydrogen ion (H+) is unstable in water.
Explanation:
H+ + H2O è H3O+
6) Alkali metals do not occur freely in nature due to their high reactivity but hydrogen does occur.
7) Hydrogen occurs in diatomic state (H2).
8) I.P. of hydrogen is very high as compared to alkali metals.
Resemblance of Hydrogen with Carbon Family (IV-A)
1) Valance shell of hydrogen is half-filled like the elements of group IV-A.
Explanation:
H (Z=1) : Capacity of K-Shell =2 , no. of electrons = 1 , % = 50%
C(z=6) : Capacity of L-Shell = 8 , no. of electrons = 4 , % = 50%
2) I.P. and E.A. of hydrogen and carbon are comparable.
3) E.N. of H and Carbon family are almost similar. [H = 2.1, C = 2.5 , Si= 2.4]
4) Both show reducing effects.
Explanation:
CuO + H2 è Cu + H2O
SnO2 + C è Sn + CO2
5) Both combine with other elements through covalent bonding.
Explanation
DIFFERENCES
1) Carbon is tetravalent but Hydrogen is a mono-valent.
2) Hydrogen is a gas at room temperature but elements of group IV-A are solids.
3) Boiling and melting points of hydrogen is very less than that of the elements of group IV-A.
Resemblance Of Hydrogen With Halogens
1) Both Hydrogen and Halogens require one electron to complete their valence shell.
2) Both hydrogen and Halogens are non-metals(Except iodine which has partial metallic character).
3) Both hydrogen and Halogens acts as negative ions when combined with metals. 4) Their molecules are diatomic.
5) Like Halogens, hydrogen can also form both ionic and covalent bond.
Explanation
Hydrogen:
NaH (ionic),
CH4 (Covalent)
Halogens:
NaCl (ionic), HCl
6) Both H and Halogens form compound with metals and non-metals.
Explanation
Hydrogen :H2S [S=non-metal]
Halogens : HCl [H = non-metal]
DIFFERENCES
1) Hydrogen has one electron in valence shell while Halogens has seven electrons.
2) Electronic configuration of H = 1S1,
Valence shell electronic configuration of Halogens = nS2, nS5
3) Unlike X- ion, H- ion is unstable in water and reacts in the following manner.
Explanation
H- + H2O èH2+ OH-
UNIQUE ATOMIC STRUCTURE OF HYDROGEN:
Hydrogen is the only element which has no neutron in its nucleus.
Conclusion
Due to above reasons it is clear that hydrogen cannot be placed in any one of the above mentioned groups.
NO!!! Hydrogen (H) is the first element on the Periodic Table. Reason Atomic No. = 1 Atomic mass( of protium) = 1 Carbon lies 6th position. Atomic No. = 6 Atomic mass = 12
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Symbols represent name of the element. They signify the position of element in periodic table.
The elements are arranged on the periodic table in order of increasing atomic number.
Hydrogen is a unique element of the Periodic Table. Due to its similarities in properties it can be placed at the top of group 1A or 4A or 7A.
1
Because hydrogen resembles both Halogens and Alkali Metals.
because its the element that created the earth
NO!!! Hydrogen (H) is the first element on the Periodic Table. Reason Atomic No. = 1 Atomic mass( of protium) = 1 Carbon lies 6th position. Atomic No. = 6 Atomic mass = 12
False (Hydrogen has the first position, Helium is the most stable)
what is lead's position on the periodic table, and it's chemical properties based on that position
Position of Periodic Table describes chemical properties. it is estimated from its position in table.
1. The wrong placing of the element Hydrogen in the periodic table. It should be placed on the right side of the periodic table, on the group of non-metals because Hydrogen is a non-metal element but in the periodic table it is placed on metals element .
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in a balloon and in a hydrogen car
Position of hafnium in the periodic table: group 4, period 6, atomic number 72.