Explanation
De Chancourtois
The fifth period starts with atomic no. 37 and ends with atomic no.54. The last electrons enters in 58, 4d or 5p orbits. So total no. of elements on fifth period is (2+10+6) = 18 elements.
It will belong to which of the following family/group and electronic configuration ?
Electronic Configuration of element with atomic no. 33 reveals that p-orbital of the element is not complete. So it is a p-block element.
In inner transition elements, the differentiating electron enters into f orbitals. So these elements are called f-block elements.
Metals used as catalyst generally belongs to d-block element. They show variable oxidation.
B, Si, Ge, As, Sb, Te and At are metalloid element.
Dubnium has atomic no. 105. In TUPAC momenclature it is known as Un-nil-pentium.
The element with same no. of shells belongs to same period. So sodium and chlorine are in same period.
Na(11) = 2, 8, 1 u(17) = 2, 8, 7.
Ionisation energy and electron affinity both are change in energy. So these are defined at enthalapy.
Order of electronegativity is
F<O<N<P
As electronagativity increases on moving left to right in a period and decreases on moving down in a group.
Be has fully filled s-subshell and hence stable configuration. So Be does not have the tendency to accept electron like Ne.
Smallest element is hydrogen. It is the lightest known element.
Ionisation energy is the energy required to pull an electron from the valence shell. But if the valence shell is fully filled it is difficult to remove an electron from a fully filled orbitals and for which a large amount of energy is required. As neon being an inert gas has fully filled orbitals, thus in order to remove en electron a large amount of energy is needed. Hence highest ionization potential.
Order of electron affinity is
F<Cl<Br<I
Chlorine has highest electron affinity.
Element which are placed diagonally in II and III period have similar properties. This is known as diagonal relationship.
II period: Li Be B C N
III period: Na Mg Al Si P
Correct order of ionization energy
C<O<N<F
On moving left to right in a period, ionization energy increases. N has half filled p-orbital.
In periodic table, after certain regular interval some properties are repeated. These properties are known as properties are known as periodic properties. Atomic mass is not a periodic property.
Order of basicity
LiOH<NaOH<kOH<CsOH
Basicity increases from top to bottom in a group in a periodic table.
When all the electrons of the element are paired, then the element is said to be diamagnetic. Only noble gases are diamagnetic in nature.
F is most electronegative element which cannot loose electron, so it exhibits (-1) state only. Na is alkali metal, it can loose electron, it exhibits (+1) state.
Order of ionisation potential is
Li>K>Cs
I.P decreases down the group and increase from left to right in a period.
Order of decreasing ionisation energy
C>Be>B>Li
Ionisation of Be is greater than B due to its stable configuration.
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