1) D-block elements are those whose last electron enters the d orbital, lying between s- and p-block elements.
2) Not all d-block elements are transition elements, which are defined as having partially filled d orbitals, while all transition elements are d-block.
3) General properties of d-block elements include high melting/boiling points due to strong metallic bonds, variable oxidation states, and many forming colored ions or complexes.
d-block elements are those in which the valence electrons enters the d orbital. d- block elements are also called transition elements. Transition elements have partially filled d orbitals.
d-block elements are those in which the valence electrons enters the d orbital. d- block elements are also called transition elements. Transition elements have partially filled d orbitals.
A brief introduction to lanthanide elements is given.
Order .ppts like this at <https://www.fiverr.com/anikmal/teamup-with-you-to-prepare-the-best-presentation>
Along with their physical and chemical properties are also shown. Helpful for quick understanding on lanthanide series.
Valence shell electron pair repulsion theory (VSEPR THEORY)Altamash Ali
Designed in a very easy manner so that u all are able to understand each and everything easily.
Gillespie & Nyholm proposed this theory ion 1957 and its is based on the direction of bonds in a polyatomic molecule.
Based on this there are several postulate that are very necessary to know before any molecule to study.
S-Block Elements - Group I Metals (Alkali metals) and Group II Metals (Alkaline Earth Metals)
Physical and Chemical Properties # General characteristics # Distiguih between both groups of metals # Some Examples of both groups metals
A brief introduction to lanthanide elements is given.
Order .ppts like this at <https://www.fiverr.com/anikmal/teamup-with-you-to-prepare-the-best-presentation>
Along with their physical and chemical properties are also shown. Helpful for quick understanding on lanthanide series.
Valence shell electron pair repulsion theory (VSEPR THEORY)Altamash Ali
Designed in a very easy manner so that u all are able to understand each and everything easily.
Gillespie & Nyholm proposed this theory ion 1957 and its is based on the direction of bonds in a polyatomic molecule.
Based on this there are several postulate that are very necessary to know before any molecule to study.
S-Block Elements - Group I Metals (Alkali metals) and Group II Metals (Alkaline Earth Metals)
Physical and Chemical Properties # General characteristics # Distiguih between both groups of metals # Some Examples of both groups metals
Introduction, position in periodic table, transition elements & inner transition elements, lanthanoids & actinoids, General trends in properties, atomic radii, atomic volume, melting points, boiling points, density, standard electrode potentials, oxidation states, Some practice questions.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
1. By : Takeen Khurshid
Submitted To: Dr Sonia Khanna
2.
3. d-block elements:
The elements of periodic table belonging
to group 3 to 12 are known as d-Block
elements. because in these elements last
electron enters in d sub shell or d orbital .
The d -block elements lie in between s- and
p-block elements in the long form of
periodic table
Definition of d-block elements
4.
5. A transition element is defined as the
one which has incompletely filled d
orbitals in its ground state or in any
one of its oxidation states. i.e.
A transition element should have
partially filled (n-1) d orbital.
Transition Elements
8. All d block elements are not transition
elements but all transition elements are d-
block elements
All d block elements are not transition
elements because d block elements like
Zinc have full d10 configuration in their
ground state as well as in their common
oxidation state which is not according to
definition of transition elements.
How are d - Block Elements &
Transition elements different?
9. GENERAL PROPERTIES OF D-BLOCK ELEMENTS
ATOMIC & IONIC SIZE
IONIZATION ENTHALPY
OXIDATION STATES OF D-BLOCK ELEMENTS
COLORED IONS
CATALYTIC PROPERTIES
MAGNETIC PROPERTIES
FORMATION OF COMPLEX COMPOUNDS
FORMATION OF INTERSTITIAL COMPOUNDS
10. GENERAL PROPERTIES OF D-BLOCK ELEMENTS
ATOMIC & IONIC SIZE
IONIZATION ENTHALPY
OXIDATION STATES OF D-BLOCK ELEMENTS
COLORED IONS
CATALYTIC PROPERTIES
11. MELTING AND BOILING POINTS (ENTHALPIES OF ATOMISATION) :
Melting and boiling
points are high.
A large number of
unpaired electrons
take part in bonding
so they have very
strong metallic bonds
and hence high m.pt
& b.pt
14. Along the rows nuclear charge increases but
the penultimate d-sub shell has poor shielding
effect so atomic and ionic size remain almost
same .
The radii of the third (5d) series are
virtually the same as those of the
corresponding members of the second
series.
15. This phenomenon is associated with the
intervention of the 4f orbital, the filling of
4f before 5d orbital results in a regular
decrease in atomic radii called Lanthanoid
contraction which essentially compensates
for the expected increase in atomic size with
increasing atomic number.
The net result of the lanthanoid contraction
is that the second and the third d series
exhibit similar radii (e.g., Zr 160 pm, Hf 159
pm)
17. Due to an increase in nuclear charge which
accompanies the filling of the inner
d- orbitals , there is an increase in ionization
enthalpy along each series of the transition
elements from left to right.
However, many small variations occur.
18. • Transition elements have variable oxidation
states ,due to very small energy difference
between (n-1)d & ns sub-shell electrons from
both the sub-shell take part in bonding
Oxidation States
19. •Low oxidation states are found when a complex
compound has ligands capable of π-acceptor character
in addition to the σ-bonding.
*For example, in Ni(CO)4 and Fe(CO)5, the oxidation
state of nickel and iron is zero.
• The elements which give the greatest number of
oxidation states occur in or near the middle of the
series. Manganese, for example, exhibits all the
oxidation states from +2 to +7.
20. Most of the transition metal compounds (ionic
as well as covalent) are colored both in solid
state & in aqueous state.
Generally the elements/ions having unpaired
electrons produce colored compound.
COLOURED IONS
25. CATALYTIC PROPERTIES
Vanadium(V) oxide,V2O5 (in Contact Process)
Finely divided iron (in Haber’s Process)
Nickel (in Catalytic Hydrogenation)
Cobalt (Synthesis of gasoline)
This property is due to-
Presence of unpaired electrons in their
incomplete d orbitals.
Variable oxidation state of transition metals.
In most cases , provide large surface area with
free valancy.
Editor's Notes
The ionization energy (IE) is qualitatively defined as the amount of energy required to remove the most loosely bound electron of an isolated gaseous atom to form a cation.
