Atoms, Elements and the periodic table

1. Atoms, Elements and the periodic table

2. Matter • All matter is composed of atoms and groups of atoms bonded together, called molecules. • Substances that are made from one type of atom only are called pure substances. • Substances that are made from more than one type of atom bonded together are called compounds. • Compounds that are combined physically, but not chemically, are called mixtures.

3. Creation of a pamphlet about the models of atomic structure In each section you must include: • Their theory about atomic structure • The technology they used to support their idea • A diagram of the model • The reason for the downfall of their theory John Dalton JJ Thomson Ernest Rutherford Neils Bohr

4. Atomic structure of an atom-what we know now… • Nucleus Proton Neutron Electron

5. n

6. What is an atom? • The smallest part of an atom. • Made up of a nucleus surrounded by electrons.

7. What is the nucleus? • The core part of the atom. • Made up of protons and neutrons. • 99.99% of the mass of the atom.

8. What is a proton? • A positively charged particle. • Found in the nucleus.

9. What is a neutron? • A neutral particle(no charge) • Found in the nucleus.

10. What is an electron? • A negatively charged particle. • Found in orbit around the nucleus.

11. chlorine nitrogen silver gold mercury oxygen hydrogen helium sodium niobium neodymium carbon

12. Elements • Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth. • Scientists have identified 90 naturally occurring elements, and created about 28 others.

13. Elements • The elements, alone or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe.

14. The most abundant element in the earth’s crust is oxygen.

15. Periodic Table • The periodic table organizes the elements in a particular way. A great deal of information about an element can be gathered from its position in the period table. • For example, you can predict with reasonably good accuracy the physical and chemical properties of the element. You can also predict what other elements a particular element will react with chemically. • Understanding the organization and plan of the periodic table will help you obtain basic information about each of the 118 known elements.

16. Why is the Periodic Table important to me? • The periodic table is the most useful tool to a chemist. • You get to use it on every test. • It organizes lots of information about all the known elements.

17. Pre-Periodic Table Chemistry … • …was a mess!!! • No organization of elements. • Imagine going to a grocery store with no organization!! • Difficult to find information. • Chemistry didn’t make sense.

18. Mendeleev • In 1869,Dmitri Ivanovitch Mendeléev created the first accepted version of the periodic table. • He grouped elements according to their atomic mass, and as he did, he found that the families had similar chemical properties.  • Blank spaces were left open to add the new elements he predicted would occur. 

19. SOME PROBLEMS… He left blank spaces for what he said were undiscovered elements. (Turned out he was right!) He broke the pattern of increasing atomic weight to keep similar reacting elements together. Dmitri Mendeléev : Father of the Table

20. The Current Periodic Table • Mendeleev wasn’t too far off. • Now the elements are put in rows by increasing ATOMIC NUMBER!! • The horizontal rows are called periods and are labeled from 1 to 7. • The vertical columns are called groups are labeled from 1 to 18.

22. Symbols • All elements have their own unique symbol. • It can consist of a single capital letter, or a capital letter and one or two lower case letters. C Carbon Cu Copper

23. Scientists have devised a ‘short hand’ way of naming elements these are called chemical symbols hydrogen = H carbon = C calcium = Ca Many symbols are the first letter of the element…carbon others are the first two letters, like calcium others use two prominent letters like cadmium…Cd still others use latin, greek or other language roots, like copper Cu (cuprium) Elements and Symbols

24. Whatever the reason for naming an element, the same rules apply only one capital letter if the symbol is two letters, it must be one upper and one lower case letter The newest of the synthetic elements have three letters, Uub for example eventually when element 112 is named it will be given a two letter symbol Elements and Symbols

25. Describe how to read the periodic table: Atomic Symbol:The atomic symbol is one or two letters chosen to represent an element ("H" for "hydrogen," etc.).  These symbols are used every where in the world   Usually, a symbol is the abbreviation of the element or the abbreviated Latin name of the element.

26. Compounds also have a short hand way of naming them these are called chemical formula H2O is a familiar example CO2 = carbon dioxide C6H12O6 = glucose H2O2 = hydrogen peroxide CuSO4 = copper sulfate Compounds and formula

27. Like symbols, formula have certain rules for their use. They always contain the elements found in the compounds they always show the relative number of atoms of each element For example: H2O tells us many things about water… the fact that it is made up of hydrogen and Oxygen the fact that there are 2x as many hydrogen atoms as oxygen atoms Chemical formula

28. Key to the Periodic Table • Elements are organized on the table according to their atomic number, usually found near the top of the square. • The atomic number refers to how many protons an atom of that element has. • For instance, hydrogen has 1 proton, so it’s atomic number is 1. • The atomic number is unique to that element. No two elements have the same atomic number.

29. Common Elements and Symbols

30. What’s in a square? • Different periodic tables can include various bits of information, but usually: • atomic number • symbol • atomic mass • number of valence electrons • state of matter at room temperature.

32. Describe the Periodic Table

33. Properties of Metals • Metals are good conductors of heat and electricity. • Metals are shiny. • Metals are ductile (can be stretched into thin wires). • Metals are malleable (can be pounded into thin sheets). • A chemical property of metal is its reaction with water which results in corrosion.

34. Properties of Non-Metals • Non-metals are poor conductors of heat and electricity. • Non-metals are not ductile or malleable. • Solid non-metals are brittle and break easily. • They are dull. • Many non-metals are gases. Sulfur

35. Properties of Metalloids • Metalloids (metal-like) have properties of both metals and non-metals. • They are solids that can be shiny or dull. • They conduct heat and electricity better than non-metals but not as well as metals. • They are ductile and malleable. Silicon

36. Groups…Here’s Where the Periodic Table Gets Useful!! • Elements in the same group have similar chemical and physical properties!! • (Mendeleev did that on purpose.) • Why?? • They have the same number of valence electrons. • They will form the same kinds of ions.

39. Families on the Periodic Table • Columns are also grouped into families. • Families may be one column, or several columns put together. • Families have names rather than numbers. (Just like your family has a common last name.)

40. Families on the Periodic Table • Elements on the periodic table can be grouped into families bases on their chemical properties. • Each family has a specific name to differentiate it from the other families in the periodic table. • Elements in each family react differently with other elements.

41. Hydrogen • Hydrogen belongs to a family of its own. • Hydrogen is a diatomic, reactive gas. • Hydrogen was involved in the explosion of the Hindenberg. • Hydrogen is promising as an alternative fuel source for automobiles

42. Hydrogen • The hydrogen square sits atop Family AI, but it is not a member of that family. Hydrogen is in a class of its own. • It’s a gas at room temperature. • It has one proton and one electron in its one and only energy level. • Hydrogen only needs 2 electrons to fill up its valence shell.

43. ALKALI METALS Group 1 • The alkali family is found in the first column of the periodic table. • Hydrogen is not a member, it is a non-metal • 1 electron in the outer shell • Soft and silvery metals • Very reactive, esp. with water • Conduct electricity • Soft enough to cut with a butter knife

44. Alkali Metals • The alkali family is found in the first column of the periodic table. • Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron. • They are shiny, have the consistency of clay, and are easily cut with a knife.

45. Alkali Metals • They are the most reactive metals. • They react violently with water. • Alkali metals are never found as free elements in nature. They are always bonded with another element.

46. What does it mean to be reactive? • We will be describing elements according to their reactivity. • Elements that are reactive bond easily with other elements to make compounds. • Some elements are only found in nature bonded with other elements. • What makes an element reactive? • An incomplete valence electron level. • All atoms (except hydrogen) want to have 8 electrons in their very outermost energy level (This is called the rule of octet.) • Atoms bond until this level is complete. Atoms with few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons during bonding.

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50. ALKALINE EARTH METALS Group 2 • 2 electrons in the outer shell • White and malleable • Reactive, but less than Alkali metals • Conduct electricity • Several of these elements are important mineral nutrients (such as Mg and Ca