This document summarizes different types of solids including metallic, ionic, covalent network, polymeric, and nanomaterials. Metallic solids are held together by delocalized valence electrons. Ionic solids are held by attraction between cations and anions. Covalent network solids form an extended network of covalent bonds making them very hard. Polymeric solids contain long chains of atoms held by covalent and weaker intermolecular forces.
Solids are characterized by their definite shape and also their considerable mechanical strength and rigidity. The particles that compose a solid material(with few exceptions), whether ionic, molecular, covalent or metallic, are held in place by strong attractive forces between them.
A silicate is an anions consisting of silicon and oxygen.
Silicates occur in earth’s crust in abundantly in the form of silicate minerals and aluminosilicate clay.
Silicate anions are often large polymeric molecules with an extense variety of structures,including chains and rings.double chains and sheets.
Silicates are extremely important materials, both natural and artificial, for all sorts of technological and artistic activities.
The attractive force which holds various constituents (atom, ions, etc.) together and stabilizes them by the overall loss of energy is known as chemical bonding. Therefore, it can be understood that chemical compounds are reliant on the strength of the chemical bonds between its constituents; The stronger the bonding between the constituents, the more stable the resulting compound would be.
Solids are characterized by their definite shape and also their considerable mechanical strength and rigidity. The particles that compose a solid material(with few exceptions), whether ionic, molecular, covalent or metallic, are held in place by strong attractive forces between them.
A silicate is an anions consisting of silicon and oxygen.
Silicates occur in earth’s crust in abundantly in the form of silicate minerals and aluminosilicate clay.
Silicate anions are often large polymeric molecules with an extense variety of structures,including chains and rings.double chains and sheets.
Silicates are extremely important materials, both natural and artificial, for all sorts of technological and artistic activities.
The attractive force which holds various constituents (atom, ions, etc.) together and stabilizes them by the overall loss of energy is known as chemical bonding. Therefore, it can be understood that chemical compounds are reliant on the strength of the chemical bonds between its constituents; The stronger the bonding between the constituents, the more stable the resulting compound would be.
Allotropes of carbon
Carbon is capable of forming many allotropes due to its valency. Well known forms of carbon include diamond and graphite. In recent decades many more allotropes and forms of carbon have been discovered and researched including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperature or extreme pressures.
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
✔Here is an introduction to the Chemistry of Life, where you will learn about Ionic, Covalent and Metallic bonds. This presentation touches briefly, but it covers the definition of three major types of chemical bonds: ionic, covalent, and metallic. Ionic bonds form due to the transfer of an electron from one atom to another. Covalent bonds involve the sharing of electrons between two atoms. Metallic bonds are formed by the attraction between metal ions and delocalized, or "free" electrons.✔
Here is a YouTube of this presentation:
➡➡➡https://www.youtube.com/watch?v=8cRQjClbeas&feature=youtu.be
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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.
Allotropes of carbon
Carbon is capable of forming many allotropes due to its valency. Well known forms of carbon include diamond and graphite. In recent decades many more allotropes and forms of carbon have been discovered and researched including ball shapes such as buckminsterfullerene and sheets such as graphene. Larger scale structures of carbon include nanotubes, nanobuds and nanoribbons. Other unusual forms of carbon exist at very high temperature or extreme pressures.
CONDUCTIVITY-TYPES-VARIATION WITH DILUTION-KOHLRAUSCH LAW - TRANSFERENCE NUMBER -DETERMINATION - IONIC MOBILITY - APPLICATION OF CONDUCTANCE MEASUREMENTS - CONDUCTOMENTRIC TITRATION
✔Here is an introduction to the Chemistry of Life, where you will learn about Ionic, Covalent and Metallic bonds. This presentation touches briefly, but it covers the definition of three major types of chemical bonds: ionic, covalent, and metallic. Ionic bonds form due to the transfer of an electron from one atom to another. Covalent bonds involve the sharing of electrons between two atoms. Metallic bonds are formed by the attraction between metal ions and delocalized, or "free" electrons.✔
Here is a YouTube of this presentation:
➡➡➡https://www.youtube.com/watch?v=8cRQjClbeas&feature=youtu.be
Check out more interesting posts on LabGirl:
➡➡➡ https://www.facebook.com/labgirldzd
Thank you! :)
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.
Chapter 1: Material Structure and Binary Alloy Systemsyar 2604
This is an introduction to material structure and periodic table system. This topic also describes microstructure of the metals and alloys solidification.
Explain covalent bond- Explain Metallic bond and what important proper.docxtodd401
Explain covalent bond?
Explain Metallic bond and what important property derives from it in metals?
Solution
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability. Nonmetals will readily form covalent bonds with other nonmetals in order to obtain stability, and can form anywhere between one to three covalent bonds with other nonmetals depending on how many valence electrons they posses. Although it is said that atoms share electrons when they form covalent bonds, they do not usually share the electrons equally.
Link : http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/General_Principles/Covalent_Bonds
Metallic bond is the reaction between molecules within metals called alkali reactive force. It was first discovered by K. Manishekar. It is the sharing of a sea of delocalised electrons amongst a lattice of positive ions, where the electrons act as a \"glue\" giving the substance a definite structure.
The electrons and the positive ions in the metal have a strong attractive force between them. Therefore metals often have high melting or boiling points. The principle is similar to that of ionic bonds.
The metallic bond accounts for many physical characteristics of metals, such as strength, malleability, ductility, luster, conduction of heat and electricity.
Because the electrons move independently of the positive ions in a sea of negative charge, the metal gains some electrical conductivity. It allows the energy to pass quickly through the electrons generating a current. Heat conduction works on the same principle - the free electrons can transfer the energy at a faster rate than other substances such as those which are covalently bonded, as these have their electrons fixed into position. There also are few non-metals which conduct electricity: graphite (because, like metals, they have free electrons), and molten and aqueous ionic compounds which have free moving ions
Link : https://simple.wikipedia.org/wiki/Metallic_bond
.
2. CLASSIFICATIONS OF
SOLIDS held together by a delocalized ―sea‖ of
Metallic solids are
collectively shared valence electrons.
This form of bonding allows metals to conduct electricity.
It is also responsible for the fact that most metals are relatively strong
without being brittle.
Ionic solids are held together by the mutual attraction
between cations and anions.
Differences between ionic and metallic bonding make the electrical
and mechanical properties of ionic solids very different from those of
metals.
Covalent-network solids are held together by an extended
network of covalent bonds.
This type of bonding can result in materials that are extremely
hard, like diamond, and it is also responsible for the unique properties
of semiconductors.
3. Polymers contain long chains of atoms, where the atoms
within a given chain are connected by covalent bonds and
adjacent chains held to one another largely by weaker
intermolecular forces.
Polymers are normally stronger and have higher melting
points than molecular solids, and they are more flexible than
metallic, ionic, or covalent-network solids.
Nanomaterials are solids in which the dimensions of
individual crystals have been reduced to the order of 1–100
nm.
As we will see, the properties of conventional materials
change when their crystals become this small.
4.
5. Crystalline and Amorphous
Solidsatoms are arranged in an orderly repeating pattern are
Solids in which
called crystalline solids.
These solids usually have flat surfaces, or faces, that make definite
angles with one another.
The orderly arrangements of atoms that produce these faces also cause
the solids to have highly regular shapes
Examples of crystalline solids include sodium chloride, quartz, and
diamond.
Amorphous solids (from the Greek words for ―without form‖) lack the
order found in crystalline solids. At the atomic level the structures of
amorphous solids are similar to the structures of liquids, but the
molecules, atoms, and/or ions lack the freedom of motion they have in
liquids. Amorphous solids do not have the well-defined faces and shapes
of a crystal.
Familiar amorphous solids are rubber, glass, and obsidian (volcanic
glass).
6. Unit Cells and Crystal
Lattices
In a crystalline solid there is a relatively small repeating
unit, called a unit cell, that is made up of a unique
arrangement of atoms and embodies the structure of the
solid.
The structure of the crystal can be built by stacking this unit
over and over in all three dimensions.
Thus, the structure of a crystalline solid is defined by (a) the
size and shape of the unit cell and (b) the locations of atoms
within the unit cell.
The geometrical pattern of points on which the unit cells are
arranged is called a crystal lattice.
The crystal lattice is, in effect, an abstract (that is, not real)
scaffolding for the crystal structure.
7.
8. To understand real crystals, we must move
from two dimensions to three.
In three dimensions, a lattice is defined by
three lattice vectors a, b, and c
These lattice vectors define a unit cell that is
a parallelepiped (a six-sided figure whose
faces are all parallelograms) and is described
by the lengths a, b, c of the cell edges and
the angles α β γ between these edges.
There are seven possible shapes for a three
dimensional unit cell are as shown
9. If we place a lattice point at each corner of a unit cell, we get
a primitive lattice.
All seven lattices that are primitive lattices.
It is also possible to generate centered lattices by placing
additional lattice points in specific locations in the unit cell.
This is illustrated for a cubic lattice for body-centered cubic
lattice has one lattice point at the center of the unit cell in
addition to the lattice points at the eight corners.
A face-centered cubic lattice has one lattice point at the
center of
each of the six faces of the unit cell in addition to the lattice
points at the eight corners.
Centered lattices exist for other types of unit cells as well.
Examples include bodycentered tetragonal and face-centered
orthorhombic.
Counting all seven primitive lattices as well as the various
types of centered lattices, there are a total of 14 three
dimensional lattices.
10.
11.
12.
13. METALLIC SOLIDS
Metallic solids, also simply called metals, consist entirely
of metal atoms.
The bonding in metals is too strong to be due to dispersion
forces, and yet there are not enough valence electrons to
form covalent bonds between atoms.
The bonding, called metallic bonding, results from the fact
that the valence electrons are delocalized throughout the
entire solid.
That is, the valence electrons are not associated with
specific atoms or bonds but are spread throughout the
solid.
We can visualize a metal as an array of positive ions
immersed in a ―sea‖ of delocalized valence electrons.
14. Electron-Sea Model
A simple model for characteristics of metals is the electron-sea
model,which pictures the metal as an array of metal cations in a ―sea‖ of
valence electrons
The electrons are confined to the metal by electrostatic attractions to the
cations, and they are uniformly distributed throughout the structure.
The electrons are mobile, however, and no individual electron is confined
to any particular metal ion.
When a voltage is applied to a metal wire, the electrons, being negatively
charged, flow through the metal toward the positively charged end of the
wire.
The high thermal conductivity of metals is also accounted for by the
presence of mobile electrons.
The movement of electrons in response to temperature gradients permits
ready transfer of kinetic energy throughout the solid.
The ability of metals to deform (their malleability and ductility) can be
explained by the fact that metal atoms form bonds to many neighbors.
Changes in the positions of the atoms brought about in reshaping the
metal are partly accommodated by a redistribution of electrons.
15.
16.
17. IONIC SOLIDS
Ionic solids are held together by the electrostatic
attraction between cations and anions—ionic bonds.
The high melting and boiling points of ionic compounds
are a testament to the strength of the ionic bonds.
The strength of an ionic bond depends on the charges
and sizes of the ions. the attractions between cations
and anions increase as the charges of the ions go up.
Thus NaCl, where the ions have charges of and , melts
at 801 °C, whereas MgO, where the ions have charges
of and , melts at 2852 °C.
The interactions between cations and anions also
increase as the ions get smaller
18. Although ionic and metallic solids both have
high melting and boiling points, the differences
between ionic and metallic bonding are
responsible for important differences in their
properties.
Because the valence electrons in ionic
compounds are confined to the anions, rather
than being delocalized, ionic compounds are
typically electrical insulators.
They tend to be brittle, a property explained by
repulsive interactions between ions of like
charge.
19.
20. COVALENT-NETWORK
SOLIDS
Covalent-network solids consist of atoms held
together in large networks by covalent bonds.
Because covalent bonds are much stronger than
intermolecular forces, these solids are much
harder and have higher melting points than
molecular solids.
Diamond and graphite, two allotropes of
carbon, are two of the most familiar covalent-
network solids.
Other examples are silicon, germanium, quartz
(SiO2), silicon carbide (SiC), and boron nitride
(BN).
21. In diamond, each carbon atom is bonded
tetrahedrally to four other carbon atoms
The structure of diamond can be derived from
the zinc blende structure if carbon atoms
replace both the zinc and sulfide ions.
The carbon atoms are sp3 -hybridized and
held together by strong carbon–carbon single
covalent bonds.
The strength and directionality of these bonds
make diamond the hardest known material.
The stiff, interconnected bond network is also
responsible for the fact that diamond is one of
the best-known thermal conductors.
Not surprisingly, diamond has a high melting
point, 3550 °C.
22. In graphite, the carbon atoms form covalently bonded layers that
are held together by intermolecular forces.
The layers in graphite are the same as the graphene sheet
Graphite has a hexagonal unit cell containing two layers offset so
that the carbon atoms in a given layer sit over the middle of the
hexagons of the layer below.
Each carbon is covalently bonded to three other carbons in the
same layer to form interconnected hexagonal rings.
Electrons move freely through the delocalized π orbitals, making
graphite a good electrical conductor along the layers
conducting electrode in batteries.
These sp2-hybridized sheets of carbon atoms are separated by
3.35 A from one another, and the sheets are held together only by
dispersion forces.
Thus, the layers readily slide past one another when rubbed, giving
graphite a greasy feel.
23. This tendency is enhanced when impurity
atoms are trapped between the layers, as
is typically the case in commercial forms of
the material.
Graphite is used as a lubricant and as the
―lead‖ in pencils. The enormous differences
in physical properties of graphite and
diamond—both of which are pure carbon—
arise from differences in their three-
dimensional structure and bonding.