Essay on structure and shape

Submitted By UtilityCheese
Words: 905
Pages: 4
Open Document
1 of 33

© Boardworks Ltd 2009

2 of 33

© Boardworks Ltd 2009

Types of crystal
The physical properties of a material depend on its structure.
Materials in which the atoms or molecules have a regular arrangement (lattice) are called crystals.
There are four basic types of crystal:


ionic – a lattice formed by positively and negatively-charged ions.



metallic – a regular lattice of positively-charged metal ions surrounded by a ‘sea’ of delocalized electrons.



macromolecular (giant covalent) – a regular lattice of atoms held together by covalent bonds.



molecular (simple covalent) – a regular lattice of covalently-bonded molecules held together by intermolecular forces.
3 of 33

© Boardworks Ltd 2009

Properties of ionic substances

4 of 33

© Boardworks Ltd 2009

Properties of sodium chloride

5 of 33

© Boardworks Ltd 2009

Properties of metallic substances

6 of 33

© Boardworks Ltd 2009

Properties of metallic and ionic crystals

7 of 33

© Boardworks Ltd 2009

Properties of metallic and ionic crystals

8 of 33

© Boardworks Ltd 2009

9 of 33

© Boardworks Ltd 2009

The structure of diamond
Allotropes are different forms of the same element.
Diamond is an allotrope of carbon, and is an example of a macromolecular crystal.
Each carbon atom is bonded by covalent bonds to four other carbon atoms, creating a rigid, very strong 3D structure. 10 of 33

© Boardworks Ltd 2009

Properties of diamond

11 of 33

© Boardworks Ltd 2009

The structure of graphite
Graphite is another allotrope of carbon. Like diamond, it is a macromolecular crystal. However, it has very different physical properties because the carbon atoms are arranged in a different way.
Each carbon atom is covalently bonded to three others in the same 2D plane, forming layers.
These layers are held weakly together by van der Waals forces, not covalent bonds.
12 of 33

© Boardworks Ltd 2009

Properties of graphite

13 of 33

© Boardworks Ltd 2009

Allotropes of carbon

14 of 33

© Boardworks Ltd 2009

Other allotropes of carbon
Another class of carbon compounds are the fullerenes.
Buckminsterfullerene is one type of fullerene. It contains 60 carbon atoms, each of which is bonded to three others by two single bonds and one double bond.
Carbon nanotubes are another type of fullerene. They are cylindrical carbon molecules. They have many potential applications, such as transporting drugs around the body and as components in electrical transistors.
15 of 33

© Boardworks Ltd 2009

The structure of iodine
Solid iodine has a molecular structure consisting of a regular arrangement of iodine molecules (I2) held in place by van der Waals forces.

The melting point of iodine is low (387 K) compared to that of diamond, because less energy is required to break van der Waals forces than covalent bonds.

16 of 33

© Boardworks Ltd 2009

The structure of ice
In ice, water molecules form four hydrogen bonds with neighbouring water molecules, creating a repeating tetrahedral structure. Usually a solid is more dense than the same material in its liquid phase. However, cold water
(around 4 °C) is denser than ice.

hydrogen bond This is because not all the water molecules are hydrogen bonded, and the mean distance between molecules is less than the hydrogen bond length.
17 of 33

© Boardworks Ltd 2009

Covalent crystals: true or false?

18 of 33

© Boardworks Ltd 2009

Covalent structures

19 of 33

© Boardworks Ltd 2009

20 of 33

© Boardworks Ltd 2009

Bonding and lone pairs
A pair of electrons in a covalent bond are
Show More

Related Documents: Essay on structure and shape

Essay on Chemistry: Art and Aaron Curry Comments

art has a very unique and abstract style, with his structures ranging from being no taller than a few inches off the ground, to massive structures more than three times as tall as the average human being. “Melt to Earth” is currently on display around the Revson Fountain on Josie Robertson Plaza, located in Lincoln Center. The 14 metal structures are exhibited in a circle with various colors, designs and shapes. Aaron Curry’s tallest structure is the one of his most prominent pieces, towering above…

Words 717 - Pages 3

Explain The Structure Of Enzymes And Explain Their Metabolic Reactions

Explain the structure of enzymes and discuss their metabolic reactions. Explain the structure of enzymes and discuss their metabolic reactions. Enzyme, a protein that catalyses a specific reaction. ‘Living cells contain thousands of different enzymes’ (Elliott, p.214), each of which catalyses (that is, accelerates without itself being changed) just one kind of reaction. In some of these reactions, small organic molecules such as amino acids, sugars, nucleotides, and lipids are broken down to…

Words 1692 - Pages 7

Week 2 Essay Quiz

scale could be more developed to give a more accurate description of substances (Grunwald, 2014). Enzymes serve a catalyst, increasing the efficiency and speed of a chemical reaction, for biochemical reactions. Enzymes are made of various structures and amino acids. Nearly twenty percent of the human body is…

Words 689 - Pages 3

Effects Of Competitive And Noncompetitive Inhibition Of Enzymes

Chapter 2 Answers to examination-style questions Answers Marks Examiner’s tips 1 (a)  and structure (of A) is complementary to A that of the active site; 1 You must be able to explain how enzymes act. (b) dea that non-competitive inhibitor (C) i binds at a site that is not the active site;  binding causes a change in the shape of the active site;  substrate is no longer able to bind to the active site; 3 Make sure that you know the different effects…

Words 693 - Pages 3

Notes On Proteins And Nucleic Acids

activates a appropriate response * Structure * Structural proteins give the cell mechanical support * Structural proteins keep the cell flexible and in their normal shape, as well as holding together the inside and membrane of the cell * Transport * Proteins are responsible for letting molecules in and out of the cell, and for carrying compounds in the body * Hemoglobin is a transport protein that carries oxygen Structure of Amino Acids Most of the proteins…

Words 1987 - Pages 8

Roman Temples Research Paper

The simplest type is known as a barrel vault . Barrel vaults consist of a line of arches in a row that create the shape of a barrel cut in half. When two barrel vaults intersect at right angles, they create a groin vault. These are easily identified by the x-shape they create in the ceiling of the vault. Furthermore, because of the direction, the thrust is concentrated along this x-shape, so only the corners of a groin vault need to be grounded. This allows an architect or engineer to manipulate the…

Words 865 - Pages 4

Essay on Design of Structures

Reaffirmed 1998 ) lndian Standard CRITERIA FOR EARTHQUAKE RESISTANT DESIGN OF STRUCTURES (Fourth First Reprint Revision ) JULY 1999 UDC 699.841 : 624.042.7 0 Copyright 1986 BUREAU MANAK OF INDIAN 9 BAHADUR STANDARDS SHAH ZAFAR MARG BHAVAN, NEW DELHI 110002 Gr 14 June 1986 IS t 1893 - 1984 Indian Standard CRITERlA FOR EARTHQUAKE RESISTANT DESIGN OF STRUCTURES ( Fourth Revision ) Earthquake Engineering Sectional Committee, BDC 39 Chairman…

Words 6240 - Pages 25

Microorganisms Is A General Term For Single Celled Organisms

Adaption increases the long-term reproductive success of a species by helping its members to survive long enough to breed. Adaption and Selection are major features in evolution. Changes in DNA can result in two ways: 1. Changing the quantity or structure of the DNA of an organism. This is known as mutation. 2. Recombining the existing DNA of two individuals. This occurs due to sexual reproduction. DNA is the genetic material in bacteria. DNA is changing by mutations and conjugation. Mutations -Changes…

Words 2760 - Pages 12

Essay on Museum visit esssya

painter used the line is such a way that it would reflect the shape of the woman who is the main character of the painting. It also tries to reflect other structure around her. The shape of the artwork informs us that the different organic shapes and even some geometric shapes have been used. The painter has used organic shape to paint the main character’s figures and shapes and she has also used geometric shape to reflect the other structures around her like tables and luggage bags. The use of light…

Words 542 - Pages 3

Elodea Cells

What factorS or structureS might be involved in determining the cells shape? The factors/structures that might be involved in determining the shape of a cell are cytoskeleton, cell wall and central vacuole. Compare and contrast the onion cells, elodea cells, and cheek cells. This requires several sentences. Explain any differences you noted other that the difference in shape? A similarity of of the three cells is that the Elodea cells, onion cells and cheek cells are eukaryotic cells. Also…

Words 683 - Pages 3