Simply following electron configurations, hydrogen (electronic configuration 1s1) and helium (1s2) should be placed in Free Printable Periodic Table groups 1 and 2, above lithium (1s22s1) and beryllium (1s22s2). While such a placement is common for hydrogen, it is rarely used for helium outside of the context of electron configurations: When the noble gases (then called “inert gases”) were first discovered around 1900, they were known as “group 0”,
if you are search best free vpn then you are serach here free vpn server eflecting no chemical reactivity of these elements known at that point, and helium was placed on the top of that group, as it did share the extreme chemical inertness seen throughout the group. As the group changed its formal number, many authors continued to assign helium directly above neon, in group 18; one of the examples of such placing is the current IUPAC table.
if you are search circumference formula then then you are serach clcik here Circumference of Cylinder Formula alkali metals, which occupy group 1. On this basis it is sometimes placed elsewhere. A common alternative is at the top of group 17 given hydrogen’s strictly univalent and largely non-metallic chemistry, and the strictly univalent and non-metallic chemistry of fluorine (the element otherwise at the top of group 17). Sometimes, to show hydrogen has properties
If you are find affect vs effect formula then you are click here affect vs effect test Another suggestion is above carbon in group 14: placed that way, it fits well into the trends of increasing ionization potential values and electron affinity values, and is not too far from the electronegativity trend, even though hydrogen cannot show the tetravalence characteristic of the heavier group 14 elements. Finally, hydrogen is sometimes placed separately from any group; this is based on
how general properties of hydrogen differ from that of any group. The other period 1 element, helium, is sometimes placed separately from any group as well. The property that distinguishes helium New Blog and Magazine themes of 2018 the rest of the noble gases (even though the extraordinary inertness of helium is extremely close to that of neon and argon) is that in its closed electron shell, helium has only two electrons in the outermost electron orbital, while the rest of the noble gases have eight.