Dmitri Mendeleev (1834-1907) and the German chemist, Lothar Meyer (1830-1895) proposed arranging elements in
They arranged elements in increasing order of atomic weights
Before the 4p orbital is filled, filling up of 3d orbitals becomes energetically favourable and there are 3d transition series of elements. This starts from scandium (Z = 21) which has the electronic configuration of .
The outer electronic configuration of f - Block elements are:
In A last electron enters f orbital.
In terms of period and group where would you locate the element with Z=114 in the periodic table?
Z=114 will present at 7th period and 4th group.
Of the following complex ions, which is diamagnetic in nature?
[Ni(CN)4]2−− is in +2 oxidation state d8 configuration and CN− is strong field ligand so causes pairing so it is a diamagnetic in nature.
According to Mendeleev 'Periodic Law' states
Mendeleev 'Periodic Law' states that the properties of the elements are a periodic function of their atomic weights.
An s orbital with one ml can accommodate x electrons, a p orbital with three ml y electrons, and a d orbital with five ml z electrons. The correct values of x, y and z are
for s orbital ml =0 it accommodate 2 electron. p orbital has ml = -1,0,+1 it can accommodate 6 electrons. d orbital has ml = -2,-1,01,2 it can accommodate 10 electrons.
The correct order for the increase in atomic radii is
As we move down the group atomic radii increases.
An ionic compound is expected to have tetrahedral structure if - lies in the range of
For tetrahedral r+ / r- lies in the range 0.225 to 0.414.
The characteristic not related to alkali metal is
Alkali metals have lowest ionization energy value.
Mendeleev arranged elements in horizontal rows and vertical columns of a table in order of their increasing atomic weights in such a way that the elements with similar properties occupied
Mendeleev arranged elements in horizontal rows and vertical columns of a table in order of their increasing atomic weights in such a way that the elements with similar properties occupied the same vertical column or group.
s-Block Elements comprise
s block comprises of alkali metal and alkaline earth metal.
The correct order for the decrease in atomic radii is
as we move along the period atomic radii decreases.
The relative tendency of an atom in a molecule to attract the shared pair of electrons towards itself is termed as its
Electronegativity is tendency of atom to attract shared pair of electrons towards itself.
The correct statement with regard to H+2 and H−2 is
H+2 is more stable than H−2
Mendeleev relied on the similarities in the empirical formulas and properties of the compounds formed by the elements. He realized that some of the elements did not fit in with his scheme of classification if the order of atomic weight was strictly followed. He therefore
Mendeleev placed the elements with similar properties together
All the orbitals in the valence shell of the noble gases
noble gases have fully filled configuration so its very difficult to alter the stable arrangement.
One of the following has ns1 as its outermost electronic configuration
alkali metals have ns1 electronic configuration.
The order of screening effect of electrons of s, p, d and f orbitals of a given shell of an atom on its outer shell electrons is:
Screening effect order follows s>p>d>f.
The magnetic moment of a transition metal ion is 15−−√15 B.M. Therefore the number of unpaired electrons present in it is
magnetic moment is [n(n+1)]1/2[n(n+1)]1/2 n is the no. of unpaired electrons.
Mendeleev proposed that some of the elements were still undiscovered and, therefore, left several gaps in the table. He left the gap under aluminium and a gap under silicon, and called these elements Eka-Aluminium and Eka-Silicon. These were later discovered and named
They were named as Gallium and Germanium respectively
d-Block Elements are characterized by the
d-Block Elements are characterized by the filling of inner d orbitals by electrons
The order of increasing metallic character is:
Elements characterized by the filling of 4f orbitals are lanthanides.
Which of the following is not an actinoid?
Terbium (Z=65) is not an actinoid.
An element with atomic number 21 is a
Sc is 21. It is transition elemant as it has incompletely filled d orbitals.