Periodic Table of Elements

1. Periodic Table of Elements

2. Objectives • Define chemistry, matter and mass • Define atomic number and mass number • Distinguish among the three classes of matter: elements, compounds and mixtures • State what symbols are and learn the first 30 on the table • Define chemical activity

3. List some of the characteristic properties of the families, halogens, the alkali metals and the inert gases • Distinguish between metal and nonmetal atoms in the terms of their electron structures • Distinguish between the groups and periods of the periodic table • State what is meant by atomic shells and sub shells

4. Periodic Table

5. 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. 

6. T h e P e r i o d i c T a b l e M o s t o f w h a t y o u n e e d i s o n i t

7. C h e m i c a l s y m b o l A t o m i c n u m b e r M a s s n u m b e r P r o t o n s i n a t o m E l e c t r o n s i n a t o m N e u t r o n s i n a t o m M e t a l / N o n m e t a l C h e m i c a l a c t i v i t y O x i d a t i o n n u m b e r E n e r g y l e v e l s E l e c t r o n c o n f i g u r a t i o n C h e m i c a l F a m i l i e s N a t u r a l / M a n m a d e P h y s i c a l s t a t e a t r o o m t e m p e r a t u r e I n f o r m a t i o n o n t h e P e r i o d i c T a b l e

8. 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.

9. 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.

10. Atomic Number • This refers to how many protons an atom of that element has. • No two elements, have the same number of protons. Bohr Model of Hydrogen Atom Wave Model

11. Atomic Mass • Atomic Mass refers to the “weight” of the atom. • It is derived at by adding the number of protons with the number of neutrons. This is a helium atom. Its atomic mass is 4 (protons plus neutrons). What is its atomic number?

12. Atomic Mass and Isotopes • While most atoms have the same number of protons and neutrons, some don’t. • Some atoms have more or less neutrons than protons. These are called isotopes. • An atomic mass number with a decimal is the total of the number of protons plus the average number of neutrons.

13. Atomic Mass Unit (AMU) • The unit of measurement for an atom is an AMU. It stands for atomic mass unit. • One AMU is equal to the mass of one proton.

14. T h e P e r i o d i c T a b l e T h e e l e m e n t s o n t h e t a b l e a r e a r r a n g e d a c c o r d i n g t o i n c r e a s i n g A t o m i c N u m b e r

17. Columns of elements are called groups or families. Elements in each family have similar but not identical properties. For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals. All elements in a family have the same number of valence electrons. Each horizontal row of elements is called a period. The elements in a period are not alike in properties. In fact, the properties change greatly across even given row. The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas. Families Periods

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

19. Symbols

20. 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

21. Common Elements and Symbols

27. What does it mean to be reactive? • 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.

28. M e t a l s i n c r e a s e N o n m e t a l s i n c r e a s e N o b l e g a s e s d o n o t r e a c t C h e m i c a l A c t i v i t y

29. 5

32. s p 1 He 2 3 d 3 4 5 6 7 4 f E n e r g y l e v e l s a n d s u b l e v e l s

33. VALENCE ELECTRONS • ELECTRONS IN THE OUTER ENERGY LEVEL OR SHELL • POSITIVE IONS HAVE FEWER ELECTRONS THAN PROTONS • NEGATIVE IONS HAVE MORE ELECTRONS THAN PROTONS

34. Valence Electrons • The number of valence electrons an atom has is indicated by the group number • Valence electrons are the electrons in the outer energy level of an atom. • These are the electrons that are transferred or shared when atoms bond together.

35. T h e O c t e t R u l e T h e m a x i m u m n u m b e r o f e l e c t r o n s i n t h e o u t e r e n e r g y l e v e l o f a n a t o m i s 8 .

36. T h e O c t e t R u l e A t o m s f o r m c o m p o u n d s t o r e a c h e i g h t e l e c t r o n s i n t h e i r o u t e r e n e r g y l e v e l .

37. T h e O c t e t R u l e A t o m s w i t h l e s s t h a n 4 e l e c t r o n s i n t h e i r o u t e r l e v e l t e n d t o l o s e e l e c t r o n s t o f o r m c o m p o u n d s .

38. T h e O c t e t R u l e A t o m s w i t h m o r e t h a n 4 e l e c t r o n s i n t h e i r o u t e r l e v e l t e n d t o g a i n e l e c t r o n s t o f o r m c o m p o u n d s .

39. PERIODIC LAW • THE PROPERTIES OF THE ELEMENTS ARE A PERIODIC FUNCTION OF THE ATOMIC NUMBER • ELEMENTS HAVE SIMILAR PROPERTIES BECAUSE THEY HAVE THE SAME NUMBER OF VALENCE ELECTRONS

40. Elements

41. 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.

42. Elements, Compounds, Mixtures • Sodium is an element. • Chlorine is an element. • When sodium and chlorine bond they make the compound sodium chloride, commonly known as table salt. Compounds have different properties than the elements that make them up. Table salt has different properties than sodium, an explosive metal, and chlorine, a poisonous gas.

43. Elements, Compounds, Mixtures • Hydrogen is an element. • Oxygen is an element. • When hydrogen and oxygen bond they make the compound water. • When salt and water are combined, a mixture is created. Compounds in mixtures retain their individual properties. The ocean is a mixture.

44. Elements, compounds, and mixtures • Mixtures can be separated by physical means. • Compounds can only be separated by chemical means. • Elements are pure substances.

46. Metals and non metals

47. +1 0 +2 +3 4 -3 -2 -1 M o s t a r e +1 o r +2 O x i d a t i o n N u m b e r

48. METALS AND NON-METALS • METALS ARE GOOD CONDUCTORS AND ARE MALLEABLE, DUCTILE AND SOLID AT ROOM TEMP. LESS THAN 4 ELECTRONS IN OUTER LEVEL • NON-METALS HAVE MORE THAN 4 ELECTRONS IN THE OUTER LEVEL • METALS GIVE UP ELECTRONS • NON-METALS GAIN ELECTRONS

49. 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.

50. 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