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Why can helium be placed in group II?
The reason it can be placed in group II is because it has 2 electrons in its outside shell (also its only shell) and the groups represent how many electrons in the elements outside shell, the reason it is normally placed in group 8 or 0 is because the first shell has a maximum of 2 electrons and all elements that have a full outside shell are placed in group 8/0 and can't normally react.
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Helium has a full outmost valence shell. It is a nobel gas. it doesn't react with other chemicals. because the atomic number is 2 so it has to be in group 18 as it also has no…ble gases.
It is in group 18 of the periodic table
Helium belongs to the 18th group which is known as noble gases/rare gases/zero group elements/inert gases. The other member are Neon(Ne)Argon(Ar)Krypton(Kr)Xenon(Xe)Radon(R…n) There is a vacant space at 118 i.e.marked as Un-Un Octium (Uuo) in the periodic table. If any element occurs that place, then it will be a rare gas.
Group 18, the noble gases.
it has a full outer shell of electrons
We all know that helium is a noble gas. It has atomic number 2 but it is placed in 18 group be because in 1st group the elements have only one electron in thier s orbital e.g.… Hydrogen, lithium, sodium, potassium etc. But helium has two electron so it cannot exist in 1 group. In second group the s orbital are same but the physical and properties of helium is different from the elements present in second group. According to modern periodic table elements which have same physical properties are placed in same group. Since helium is an inert gas and its physical properties are similar to the other elements of the 18 group and also helium discoverd late so that hilium can be put in the 18 group
helium is in group 18
The outer most orbitals of helium and other noble gases have completely filled orbitals. Hence helium is placed along with the other noble gases.
Noble gases / group 18 elements
group 18 for helium and group 14 for carbon
Similar to group 18 elements (or noble gases), helium is chemically inert and it has completely filled orbitals. Hence helium is place along with group 18 elements.
Since 2 electrons fills it's outer shell it is considered an inert gas.
It isn't, it is in group viii and that is due to the full outer shell or 1s orbital.
In Noble Gases
noble gases atomic number 2 chemical symbol He