Chapter 5: The Periodic Table. Element song

Transcription

1 Chapter 5: The Periodic Table Element song Section 5.1: Organizing the elements 1.How did Mendeleev arrange the elements in his periodic table? 2.How are elements arranged in the modern periodic table? Periodic table Video 1

2 Periodic Table 2

3 New periodic tables have found creative ways to arrange the elements. 3

4 A Typical Nuclide on the periodic table: CCarbon Average atomic mass - Protons + neutrons -Always a decimal Element Symbol -1 st letter is always capitalized -2 nd letter is always lowercase Element name Atomic Number - number of protons Recognizing a Pattern Dimitri Mendeleev, the father of the periodic table. Russian chemist, organized elements, In 1869, Mendeleev Published the first Periodic Table 4

5 Recognizing a Pattern Observed the mass, reactivity, and general properties of various elements. Noticed patterns among the elements Arranged elements in rows by increasing atomic mass. Recognizing a Pattern He started a new row each time the properties of elements repeated. So, elements in the same column have similar properties. His table was used to predict elements that had yet to be discovered. (blank spaces) 5

6 Properties of Elements Recognizing a Pattern I helped recognize the periodic table He corrected discrepancies Mendeleev had some with the properties of some elements fitting in with their assigned groups. Moseley arranged elements by their atomic number, or number of protons. 6

7 The Modern Periodic Table Listed in order of increasing number of protons When you do this the properties of the elements repeat. Periodic Law- when the elements are arranged in order of increasing number of protons, the properties tend to repeat in a pattern The Modern Periodic Table Atomic Mass o An atomic mass unit or AMU is equivalent to the mass of one proton/neutron. o Atomic mass of an element refers to the number of protons and neutrons in found in its nucleus. o Electrons have virtually no mass 7

8 The Modern Periodic Table Atomic Mass is Average Mass Atomic mass refers to the average mass of one atom of a particular elements. Masses of the isotopes of the same atom are averaged. Atomic Mass is Average Mass For example.99% of all the helium atoms in the world have 2 neutrons. However, 3 out of every 1,000 have 3 neutrons instead of 2. Therefore, on the Periodic Table helium has an atomic mass of AMU s 8

9 The Modern Periodic Table Atomic Number o Atomic Number refers to the number of protons in an atom s nucleus o Elements are arranged on the Periodict Table according to atomic number. Atomic Number ***Atomic number (# of protons) is a unique property*** Periodic Table Organization In stores, items that are similar are grouped together so they are easier to find. Elements are arranged in a certain order based on the number of protons an atom of an element has. 9

10 Periodic Table Organization The table puts elements into groups with similar characteristics. Allows us to recognize trends over the whole array of elements. 10

11 Periodic Table Organization Atomic Mass and Atomic Number increases as you move across and down. Periodic Table Organization Periods Period- a horizontal row of elements in the periodic table. Protons and electrons increases as you move across a period from left to right. (Same # of electron orbitals) 11

12 Periods Periods Periods All of the elements in a period have the same number of atomic orbitals. Shows how many energy levels the atom has. 12

13 Periods Elements become less metallic as you move to the right across each period. Periodic Table Organization Groups Group- a vertical column of elements in the periodic table. Also called a family 18 individually numbered columns 13

14 Groups Groups Every element in the same family has similar properties. 14

15 Groups (Same # of valence electrons) 15

16 Groups Lithium- Grp 1 Hydrogen- Grp 1 Grp 1 has 1e- Grp 2 has 2e- Grp 13 (3) has 3e- Grp 14 (4) has 4e- Grp 15 (5) has 5e- Grp 16 (6) has 6e- Grp 17 (7) has 7 e- Grp 18 (8) has 8e- (a full octet). Beryllium- Grp 2 Memorize this rhyme. 1+, 2+, 3+, skip, 3-, 2-, 1-, zip This tells you the Ionic charge and oxidation numbers for the elements in the 8 REPRESENTATI VE GROUPS, 1A-8A, as you count form left to right. 16

17 Is the circled area a period or group on the periodic table? Group/Family Question How was Mendeleev s periodic table arranged? A.By increasing atomic mass B.By decreasing atomic mass C.By increasing atomic number D.By decreasing atomic number 17

18 Section 5.2: Exploring the Periodic Table Why do elements within a group of the periodic table have similar chemical properties? What happens to an atom that gains or loses electrons? What are the three main categories of elements? 18

19 The Role of Electrons Neutral atom: # of protons (+) = # of electrons (-) The trends in the periodic table are a result of electron arrangement. The Role of Electrons The chemical properties of each group are largely determined by the number of valence electrons. What group does it belong too? 19

20 The Role of Electrons Valence Electrons Rhyme 1+, 2+, 3+, skip, 3-, 2-, 1-, zip The Role of Electrons Location If you know where an element is located on the periodic table, you can figure out how its electrons are arranged. 20

21 Ne is at the end of pd 2, its C is Li in H is pd & in He 2pd are 2 in pd 1 C has H Li has 2e-12 in e- the in first its s-orbital, level s-orb, and He 2e- 1 e- in in second an s- 3 level p-orbitals has s-orb, 2 e- in and in the s-orb. 2 second are e- in one full. energy p-orbital. level. Electron Configurations Practice Write the complete ground state electron configurations for the following: 1s 2 2s 1 1) lithium 1s 2 2s 2 2p 4 2) oxygen 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3) calcium 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2 4) titanium 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 5) rubidium 6) lead 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 2 7) erbium 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 12 21

22 What is the Rhyme to help you remember the charge ions for valence electron groups? Ion Formation Atoms with a charge Different number of protons and electrons Form by changing the number of electrons Ionization is the process of adding or removing from an atom. It happens to atoms that do NOT have their outermost energy levels filled with electrons. 22

23 Ion Formation The two types of ions are: Cation- an ion with a positive charge. (+) An electron is removed from an atom and the result is this positive ion. Ex) elements in Group 1, 2, &13 Anion- an ion with a negative charge (-) An electron is added to the atom to make a more negative ion. Ex) elements in groups 15, 16, &17 e- removed e- added Lithium has one valence electron, so it would rather give it away than collect 7 more electrons to fill its outer energy level. Fluorine has 7 valence electrons, so it would rather collect 1 more electron to fill its outer energy level, than give 7 away. Hydrogen has one valence electron; it's in the Alkali Metal Family All other elements in this family, Li, Na, K, Rb, and Cs, also have only one valence electron. 23

24 Fluorine has seven valence electrons This places it in the halogen family Alkali metals have one valence electron - Sodium Halogens have seven valence electrons - Chlorine What s going to happen? 24

25 Sodium Chloride Group 1 Group 7 Periodic Trends First Ionization Energy energy required to remove an e - from a neutral atom First Ionization Energy Increases to the RIGHT and UP

26 How Are Elements Classified? Elements in each category have similar properties Three main categories of elements: Semiconductors How Are Elements Classified? 26

27 Semiconductors How Are Elements Classified? Metals Characteristics: Shiny Malleable- can be flattened into sheets Ductile- can be stretched or shaped into wires Good conductors of heat and electricity Most are solids at room temperature. 27

28 Metals Families How Are Elements Classified? Metalloids (Semi-Conductors) Characteristics: Varying ability to conduct electricity Can be used to make semiconductors (materials that can conduct electricity ONLY under certain conditions) 28

29 How Are Elements Classified? Non Metals Characteristics: Mostly dull (not shiny) Brittle, not malleable or ductile Poor conductors of heat and electricity Many are gases at room temperature. Halogens and Noble Gases 29

30 Section 5.3: Families of Elements What does each element family have in common? What are the families of metals? What are some of the families of nonmetals? What are semiconductors? Metals Almost 75% of all elements are classified as metals. They are classified based on their physical properties: hardness, shininess, malleability, conductivity, magnetism, and ductility. 30

31 Metals Chemical properties: The ease and speed in which an element reacts with other elements is called its reactivity. Metals show a wide range of chemical properties, or reactivity. Iron will react with oxygen in the air to form iron oxide (rust). Gold and chromium are unreactive. Alloys Metals An alloy is a mixture of metals Combine the beneficial attributes of 2 or more metals Iron rusts easily, but when mixed with vanadium and chromium, it forms stainless steel. Copper is soft and malleable, but when mixed with tin, it forms bronze an attractive and durable alloy. 31

32 Metals Families of metals: Alkali metals Alkaline-earth metals Transition metals Metals Alkali Metals Least Reactive Group 1 Very reactive 1 valence electron Form positive ions because electron is easily removed. +1 Most Reactive 32

33 Metals Alkali Metals Soft and shiny metals Are usually found in nature combined as a compound. Are stored in oil to prevent their reacting with water. Francium: Incredibly reactive in water. Metals Alkaline- earth metals Group 2 Are harder, denser, stronger, and have higher melting points than alkali metals. Highly reactive, but not as much as alkali metals 2 valence e-. Form positive ion 2+ Not found uncombined in nature. Calcium makes up seashells, corals, bones & teeth. 33

34 Transition Metals Metals Groups 3-12 Less reactive Usually found alone (not in compound form) Can lose 1, 2, or 3 e- to form cations They can use the inner shell electrons to bond before using the outer shell. Are harder, more dense, and have higher melting points than alkali or alkaline metals (except mercury which is a liquid at room temp). Used in jewelry, plumbing, light bulb filaments. Transition Metals Lanthanides and Actinides Also known as the rare earth elements Rare, soft, malleable metals. Some actinides are highly radioactive (they have unstable nuclei) 34

35 Transition Metals Good conductors Malleable and ductile High Density High Luster (shiny) Conducts heat well Most solid Except Hg Nonmetals All 17 nonmetals are extremely important to living things. Right of the zigzag line on the P.T, except Hydrogen Most are gases, some are crumbly solids, and Bromine is the only liquid. 35

36 NonMetals Chemical properties Most react easily to form compounds. Metal elements transfer their valence electrons to the nonmetal when combine. Nonmetals with other nonmetals, valence electrons are shared. NonMetals Poor Conductors of electricity Dull in color (no shine) Transparent/Translucent Brittle (break when hit) Poor conductors on heat 36

37 They exist as a (s), (l), (g). Solid Liquid Gas S Sulfur Br Bromine Cl Chlorine 37

38 Oxygen Family Nitrogen Family Carbon family Halogens NonMetals Families of nonmetals: Group 17 and are very reactive. Poisonous as gas, but form compounds that are very useful. NonMetals Families of nonmetals: The Noble Gases Full valence shell (8 electrons). Octet rule Except Helium Do not react at all with any other elements. Colorless, odorless gases at room temp Glow brightly when electricity passes through them. 38

39 Who is in the family? Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn) What About Hydrogen? Hydrogen Family Reactive Colorless, odorless gas at room temp Explosive reaction with oxygen stands alone 39

40 Metalloids/Semiconductors On the border between the metals and the nonmetals are the metalloids. Metalloids have some properties of metals and some properties of non-metals. As semiconductors they re varying ability to conduct electricity makes them useful in industry Metalloids/Semiconductors 40

41 Metalloids/Semiconductors Semi-conductor Can luster Brittle Synthetic elements All elements greater than atomic # 92 are man-made (synthetic). Are radioactive. Technium- 99 most stable isotope, 56 n Promethium-147, used in some glow-in-the-dark paints. Americium-241, found inside smoke detectors *** radioactive elements are harmful even in small amounts, so do not handle them unprotected. 41

42 Alkali Metals Alkaline Earth Metals Transition Metals Boron Family Carbon Family Nitrogen Family Oxygen Family Halogens Noble Gases METALLOIDS/SEMIMETALS Lanthanide Series Actinide Series 42

43 The properties of the elements Metals Nonmetals - Luster Shininess -Malleable Being able to flatten and bend -Ductile Can stretch or be pulled -Conductive Heat and Electric The most important is silicon Metalloids are in-between -Dull no luster -Brittle Cracks, fractures, and breaks easily in solid form -Insulator Does not allow Heat and Electric to pass Important Families on the periodic table Column and name Alkali metals Alkali earth metals Alkali metals Alkali earth metals Characteristics Extremely soft cut with a butter knife Most reactive metals Not found as a pure metal in nature Soft but not as soft as alkali metals Second most reactive metals Not found as a pure metal in nature but has its uses Magnesium fire starters. 43

44 Important Families on the periodic table Column and name Halogens Noble Gases Characteristics Most reactive nonmetals Combine with alkali and alkali metals to make Salts like NaCl Used as Disinfectants NO REACTION Alkali earth metals Alkali metals Halogens Noble Gases 44