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- 1. Elements and compounds By Sidra, Manahil and Rida of class 7N
- 2. Differences between Elements and Compounds Elements Elements are those substances which cannot be further subdivided in to other substances. Examples are Sodium, iron, oxygen and many more. Compounds Compounds are those substances that consist of few or more elements which have been chemically combined. Examples: Water, Sodium Chloride.
- 3. Compounds Compounds are those substances made of elements and elements are those substances which are made of atoms and nothing else. Compounds can be anything. This includes us, human beings which are made of solid, liquid and gas and those can be further subdivided in to a couple of compounds which can be sub divided in elements. Like gas. Human beings contain gas. Gas is made up of these gases in the body: Carbon Oxygen Nitrogen and more. You can see in the pic that water is made up of hydrogen and oxygen. This makes water. Water is an compound and hydrogen gas and oxygen gas are elements.
- 4. Elements Elements are those substances which cannot be further subdivided by even chemical reactions. A element is a pure substance only formed by a single type of atom. There are 112 elements which of 96 are natural while only 16 of them are man made. The 2 most abundant elements of this universe are known as helium and hydrogen.
- 5. The periodic table The periodic table is a table of elements. This table is divided and coloured in to elements that are metallic and non metallic.
- 6. Elements and there chemical symbols You can see in the table later that there is a appropriate chemical symbol for every element. All these elements can be represented easily by these chemical symbols so that it is easy to read them out. These can be also said using the german or latin name to name things easily when the English name is already taken. Just like for iron. We say Fe because the name in german or latin is ferrum as iron name is already taken for iodine.
- 7. A few symbol examples.
- 8. You can view the table below.
- 9. Reading the periodic table The periodic table is read in a certain manner. The top number for each element is its atomic number. This is the number of protons in each atom of that element. The one-letter or two-letter symbol in each tile is the element symbol. The symbol is an abbreviation for the full element name. Element symbols make it much easier for chemists to write chemical formulas and equations. The bottom number in each element tile is the atomic weight or atomic mass. This value is the average mass of atoms of that element that occur naturally. Rows of elements are called periods. The period number of an element signifies the highest unexcited energy level for an electron in that element. The number of elements in a period increases as you move down the periodic table because there are more sublevels per level as the energy level of the atom increases. Columns of elements help define element groups. Elements within a group share several common properties.
- 10. Metals This is a few examples to recognize metals: usually solid at room temperature (except mercury) metallic-looking hard shiny good conductors of heat and electricity
- 11. Non metals These are a few examples to recognize non metals: often form brittle solids lacking in metallic luster poor conductors of heat and electricity
- 12. Pie chart
- 13. Uses of elements Elements are used to make compounds and compounds are used to make NEARLY EVERYTHING. Elements help in making chemical reactions to make more elements Elements are the main building of science and science is developing because of it. We breath from oxygen. Other elements are used to make other things like water when oxygen is mixed with hydrogen.
- 14. Examples of uses of elements: Chalk: made of; calcium,carbon,oxygen. Sugar: carbon, hydrogen, oxygen Polythene: carbon, hydrogen
- 15. Gases in the human body
- 16. Some tidbits you should now The Russian scientists , Dmitri Ivanovich Mendeleev (1834-1907), was the first to arrange the 63 known elements during his time according to their properties in the periodic table . He also predicted the existence and properties of new elements which were yet to be discovered.
- 17. Summary of the chapter An element is a substance which cannot be broken down into simpler substances by chemical reactions A chemical reaction is a process in which new substances are formed . There are more than 100 elements , about 90 of which occur naturally . All other materials are made from elements hydrogen , oxygen ,helium , carbon , silicon and many more are examples of elements Elements can be classified by being non metal or metal elements have many uses and applications in daily life . The uses and applications of elements depend on their properties.
- 18. Trivia time Which one of the following is NOT an element: There are ____________ elements a) Magnesium a) 120 b) Helium b) 168 c) Aspirin c) 105 d) Sodium d) 112 Water is made up of oxygen and ________ which one of the chemical symbol stands for hydrogen a) Carbon dioxide a) HE b) Hydrogen b) H c) Nitrogen c) AU d) Argon d) HN
- 19. Thank you for listening By Manahil, Sidra , Rida of class 7N you can contact us at: Sidraashraf2008@gmail.com usmanimanahil09@gmail.com Ridatariq1616@gmail.com