1. Bonding & The periodic Table

2. Structure of Matter All matter is formed from atoms. All matter is formed from atoms. If broken apart, almost all atoms contain three smaller particles called protons, neutrons, and electrons. If broken apart, almost all atoms contain three smaller particles called protons, neutrons, and electrons. Protons and neutrons cluster together in the atom’s center, called the nucleus. Protons and neutrons cluster together in the atom’s center, called the nucleus.

3. Comparing Atoms The number of protons determines an element. The number of protons determines an element.

4. Atomic Structure & Forces 2 Main Regions of an Atom 2 Main Regions of an Atom Electron Cloud – Region of space around the nucleus where electrons exist Electron Cloud – Region of space around the nucleus where electrons exist Electrons – Tiny negatively charged particle about 1,700 times smaller than a proton or neutron Electrons – Tiny negatively charged particle about 1,700 times smaller than a proton or neutron Electrons are attracted to the positive charges in the nucleus Electrons are attracted to the positive charges in the nucleus Electrons are organized into as many as seven energy levels, depending on the number of electrons Electrons are organized into as many as seven energy levels, depending on the number of electrons Each energy level is broken into anywhere from 1 to 7 orbitals Each energy level is broken into anywhere from 1 to 7 orbitals Orbital – actual region of space where electrons exist; each orbital has a distinct shape Orbital – actual region of space where electrons exist; each orbital has a distinct shape

5. Atomic Structure & Forces 2 Main Regions of an Atom 2 Main Regions of an Atom Nucleus – Very dense positively charged center of the atom Nucleus – Very dense positively charged center of the atom Makes up only 0.00000000000001% of volume of the atoms, but contains more than 99.9% of the mass. Makes up only 0.00000000000001% of volume of the atoms, but contains more than 99.9% of the mass. Composed of positively charged protons and neutral neutrons Composed of positively charged protons and neutral neutrons

6. Atomic Structure & Forces Since protons are positively charged and very close together, we should expect an enormous repulsive force, that should break the nucleus apart Since protons are positively charged and very close together, we should expect an enormous repulsive force, that should break the nucleus apart However, non-radioactive elements have very stable nuclei that have not changed since shortly after the formation of the universe However, non-radioactive elements have very stable nuclei that have not changed since shortly after the formation of the universe There must be some other attractive force in the nucleus There must be some other attractive force in the nucleus

7. Atomic Structure & Forces Strong Nuclear Force Strong Nuclear Force Attractive force between any two nuclear particles (protons, neutrons) Attractive force between any two nuclear particles (protons, neutrons) Only acts over a very short distance Only acts over a very short distance Overcomes the repulsive force between the positive protons Overcomes the repulsive force between the positive protons The Role of Neutrons The Role of Neutrons Neutrons make the nucleus more stable by adding to the strong nuclear force, without adding positive, repulsive charges Neutrons make the nucleus more stable by adding to the strong nuclear force, without adding positive, repulsive charges

8. Chemical and Physical Properties Physical Property – defines the physical state of a material Physical Property – defines the physical state of a material Temperature, color, shape, mass, volume, weight, texture, structure, etc. Temperature, color, shape, mass, volume, weight, texture, structure, etc. Physical Changes – Any change that does not affect the identity of the atoms or molecules in the material Physical Changes – Any change that does not affect the identity of the atoms or molecules in the material Bending, Phase changes, breaking, heating, etc Bending, Phase changes, breaking, heating, etc

9. Chemical and Physical Properties Chemical Properties – define the chemical reactivity of a substance Chemical Properties – define the chemical reactivity of a substance Ex: Reacts violently with water, decomposes in oxygen, etc Ex: Reacts violently with water, decomposes in oxygen, etc Chemical Changes – results in the formation of new molecules as atoms are rearranged Chemical Changes – results in the formation of new molecules as atoms are rearranged

10. Indicators of a Possible Chemical Change Formation of a Precipitate – insoluble solid Formation of a Precipitate – insoluble solid Exothermic Reaction - Increase in temperature Exothermic Reaction - Increase in temperature Formation of a gas without heating Formation of a gas without heating Endothermic Reaction - Decrease in temperature Endothermic Reaction - Decrease in temperature Change in color Change in color Evolution of Light without heating Evolution of Light without heating Change in smell Change in smell Change in taste Change in taste

11. Chemical or Physical Change? Leaf Changing Colors Leaf Changing Colors Chemical Chemical Tarnishing Silver Tarnishing Silver Chemical Chemical Burning Calories Burning Calories Chemical Chemical Glass Breaking Glass Breaking Physical Physical Egg Frying Egg Frying Chemical Chemical Wax Burning Wax Burning Chemical Wax Melting Wax Melting Physical Water Freezing Water Freezing Physical Wind Blowing Wind Blowing Physical Bomb Exploding Bomb Exploding Chemical Indicate whether each of the following is a chemical or physical change.

12. Periodic table The chemical symbol is an abbreviation of the element’s name. The chemical symbol is an abbreviation of the element’s name. The atomic number is the number of protons all atoms of that element have in their nuclei. The atomic number is the number of protons all atoms of that element have in their nuclei.

13. The Periodic Table of Elements The symbols for some elements don’t always obviously match their names. The symbols for some elements don’t always obviously match their names.

14. Isotopes Isotopes are atoms of the same element that have different numbers of neutrons. Isotopes are atoms of the same element that have different numbers of neutrons. These are all isotopes of hydrogen. These are all isotopes of hydrogen.

15. Isotopes

16. Structure of the Periodic Table Atomic number – number of protons (& in a neutral atom- the # of electrons) Atomic number – number of protons (& in a neutral atom- the # of electrons) The number of protons defines the identity of the atom The number of protons defines the identity of the atom Atomic Mass – Average mass of protons and neutrons combined. atomic mass units (amu) Atomic Mass – Average mass of protons and neutrons combined. atomic mass units (amu) The atomic mass is the average mass of all the known isotopes of the element. The atomic mass is the average mass of all the known isotopes of the element. Oxidation Number – charge of the atom based on whether the atom needs to lose or gain electrons to become stable. Oxidation Number – charge of the atom based on whether the atom needs to lose or gain electrons to become stable.

17. Mass Number The total number of protons and neutrons in the nucleus of an atom is called the mass number. The total number of protons and neutrons in the nucleus of an atom is called the mass number. The mass number of an element is the total number of protons and neutrons in the nucleus. The mass number of an element is the total number of protons and neutrons in the nucleus.

18. Mass Number

19. Structure of the Periodic Table The Periodic Table is organized into 18 columns and 7 rows The Periodic Table is organized into 18 columns and 7 rows The rows are called periods The rows are called periods The columns are called Families or Groups The columns are called Families or Groups Elements in the same Family or Group have similar properties Elements in the same Family or Group have similar properties

20. Elements that are part Elements that are part of the same group act alike. Dimitri Mendeleev (1834- 1907) organized information about all the known elements in a table that visually organized the similarities between them. Dimitri Mendeleev (1834- 1907) organized information about all the known elements in a table that visually organized the similarities between them. Mendeleev placed each element on the table in a certain row and column based on its properties. Mendeleev placed each element on the table in a certain row and column based on its properties.

21. Structure of the Periodic Table 1 st Alkali Metals 1 st Alkali Metals 2 nd Alkaline Earth Metals 2 nd Alkaline Earth Metals 17 th Halogens 17 th Halogens 18 th Noble Gasses 18 th Noble Gasses 3 rd -12 th Transition Metals 3 rd -12 th Transition Metals

22. Structure of the Periodic Table Stair Stepper = METALLOIDS Stair Stepper = METALLOIDS The two rows at the bottom actually fit inside the 6 th and 7 th Periods, and are known as Lanthanide & Actinide Series The two rows at the bottom actually fit inside the 6 th and 7 th Periods, and are known as Lanthanide & Actinide Series Metals are to the left, Non-metals to the right of the stair stepper Metals are to the left, Non-metals to the right of the stair stepper

23. Structure of the Periodic Table The Periodic Table also tells us about the electron structure of an atom The Periodic Table also tells us about the electron structure of an atom The PERIOD number represents the energy level of the electrons The PERIOD number represents the energy level of the electrons The GROUP number represents the number of electrons in the outer energy level The GROUP number represents the number of electrons in the outer energy level Ex: Na is in a Group 1 element, therefore it has one electron in the outer energy level Ex: Na is in a Group 1 element, therefore it has one electron in the outer energy level

24. The Role of Electrons in Bonding The sharing or transfer of electrons is what holds atoms together in a molecule or compound The sharing or transfer of electrons is what holds atoms together in a molecule or compound Typically, only the electrons in the outer energy level are used for bonding. Typically, only the electrons in the outer energy level are used for bonding. This means that an atom’s chemical reactivity is defined by the number of electrons in its outer energy level This means that an atom’s chemical reactivity is defined by the number of electrons in its outer energy level OR how badly the element wants to lose or gain electrons OR how badly the element wants to lose or gain electrons Valence Electrons Valence Electrons outer shell electrons in “s” & “p” columns (total 8 to be stable) The outer energy level is called the Valence Shell The outer energy level is called the Valence Shell

26. The Role of Electrons in Bonding Octet Rule Octet Rule all elements want 8 valence shell electrons (Noble Gas Wannabe’s) In addition, all atoms want to have a full valence shell (8 valence electrons) In addition, all atoms want to have a full valence shell (8 valence electrons) Atoms react with one another in an attempt to gain or lose electrons to fill their valence shell Atoms react with one another in an attempt to gain or lose electrons to fill their valence shell During a reaction, electrons can be shared or completely transferred During a reaction, electrons can be shared or completely transferred

27. Comprehension Check How many valence electrons does phosphorus have? How many valence electrons does phosphorus have? 5 How many electrons does phosphorus have to gain or lose in order to fill its valence shell? How many electrons does phosphorus have to gain or lose in order to fill its valence shell? Lose 5, Gain 3 Lose 5, Gain 3

28. PWYR – Valence Schmalence tin tin 4 arsenic arsenic 5 strontium strontium 2 bromine bromine 7 sodium sodium 1 tellurium tellurium 6 gallium gallium 3 krypton krypton 8

29. PWYR - To Gain or Not to Gain nitrogen nitrogen Gain 3 Gain 3 beryllium beryllium Lose 2 Lose 2 xenon xenon None None carbon carbon Gain/Lose 4 Gain/Lose 4 oxygen oxygen Gain 2 lithium lithium Lose 1 chlorine chlorine Gain 1 boron boron Lose 3

30. Types of Bonds 2 Main Types of Chemical Bonds 2 Main Types of Chemical Bonds Ionic Bonds – Results from the complete transfer of electrons (metal & Non metal) Ionic Bonds – Results from the complete transfer of electrons (metal & Non metal) Ions: Ions: charged particle or atom (b/c lost or gained electrons) Cation loses electrons and is positive Anion gains electrons and is negative Covalent Bonds – Results from the sharing of electrons (non metal & non metal----tug-o-war) Covalent Bonds – Results from the sharing of electrons (non metal & non metal----tug-o-war)

31. Oxidation Numbers Oxidation Numbers tell us how many electrons an atom loses or gains Oxidation Numbers tell us how many electrons an atom loses or gains Positive oxidation= atom lost electrons Positive oxidation= atom lost electrons Negative oxidation= numbers atom gained electrons Negative oxidation= numbers atom gained electrons Some atoms have more than one possibility (transition metals—look to the non metal to find charge) Some atoms have more than one possibility (transition metals—look to the non metal to find charge)

32. Predicting Bonding We can predict which atoms will bond based on their oxidation numbers We can predict which atoms will bond based on their oxidation numbers Ex 1: Na has a +1 Oxidation Number; it wants to lose one electron; Cl has a -1 Oxidation Number; it wants to gain one electron Ex 1: Na has a +1 Oxidation Number; it wants to lose one electron; Cl has a -1 Oxidation Number; it wants to gain one electron These atoms will react quickly an violently in a 1:1 ratio to give NaCl These atoms will react quickly an violently in a 1:1 ratio to give NaCl

33. Predicting Bonding We can predict which atoms will bond based on their oxidation numbers We can predict which atoms will bond based on their oxidation numbers Ex 2: Ca has a +2 Oxidation Number; it wants to lose two electron; F has a -1 Oxidation Number; it wants to gain one electron Ex 2: Ca has a +2 Oxidation Number; it wants to lose two electron; F has a -1 Oxidation Number; it wants to gain one electron Ca will give one of its valence electrons to one F and the second electron to a second F, giving CaF 2 Ca will give one of its valence electrons to one F and the second electron to a second F, giving CaF 2

34. Comprehension Check What compound is formed when Ba reacts with Br? What compound is formed when Ba reacts with Br? BaBr 2 BaBr 2 What compound is formed when Be reacts with O? What compound is formed when Be reacts with O? BeO BeO What compound is formed when Al reacts with I? What compound is formed when Al reacts with I? AlI 3 AlI 3

35. PWYR – Family Bonds 1 of 2 sodium, chlorine sodium, chlorine NaCl NaCl calcium oxygen calcium oxygen CaO CaO gallium, phosphorus gallium, phosphorus GaP GaP carbon, beryllium carbon, beryllium Be 4 C 2 Be 4 C 2 aluminum, chlorine aluminum, chlorine AlCl 3 sodium, phosphorus sodium, phosphorus Na 3 P barium, chlorine barium, chlorine BaCl 2 strontium, nitrogen strontium, nitrogen Sr 3 N 2

36. PWYR – Family Bonds 2 of 2 When Groups I and VII elements bond what is the ratio of the atoms? When Groups I and VII elements bond what is the ratio of the atoms? 1:1 1:1 When Groups II and V elements bond what is the ratio of the atoms? When Groups II and V elements bond what is the ratio of the atoms? 3:2 3:2 When Groups III and IV elements bond what is the ratio of the atoms? When Groups III and IV elements bond what is the ratio of the atoms? 4:3 4:3

37. Metals & Oxidation Numbers When metals with multiple oxidation numbers bond to non-metals, more than one compound is formed. When metals with multiple oxidation numbers bond to non-metals, more than one compound is formed. Since all the metals (except antimony and rhenium) are positive, the non-metals must use their negative oxidation number. Since all the metals (except antimony and rhenium) are positive, the non-metals must use their negative oxidation number. Ex: molybdenum and oxygen Ex: molybdenum and oxygen MoO, Mo 2 O 3, Mo 2 O 4, Mo 2 O 5, MoO 3 MoO, Mo 2 O 3, Mo 2 O 4, Mo 2 O 5, MoO 3

38. PWYR – Oh the Possibilities titanium and chlorine titanium and chlorine TiCl 3, TiCl 4 TiCl 3, TiCl 4 thallium and phosphorus thallium and phosphorus Tl 3 P, TlP Tl 3 P, TlP tantalum and oxygen tantalum and oxygen Ta 2 O 5 Ta 2 O 5 ruthenium and carbon ruthenium and carbon Ru 2 C, Ru 4 C 3, RuC, Ru 2 C 3, RuC 2, Ru 2 C, Ru 4 C 3, RuC, Ru 2 C 3, RuC 2,

39. Non-metals & Oxidation Numbers Atoms with multiple oxidation numbers can react to form multiple compounds depending on which oxidation numbers they chose. Atoms with multiple oxidation numbers can react to form multiple compounds depending on which oxidation numbers they chose. Ex: If bromine and nitrogen reacted, one would have to be positive (lose e - ) and the other negative (gain e - ). Ex: If bromine and nitrogen reacted, one would have to be positive (lose e - ) and the other negative (gain e - ). Let’s assume bromine takes its -1 oxidation number, nitrogen can be 2, 3, 4, or 5 Let’s assume bromine takes its -1 oxidation number, nitrogen can be 2, 3, 4, or 5 NBr 2, NBr 3, NBr 4, NBr 5 NBr 2, NBr 3, NBr 4, NBr 5

40. Non-metals & Oxidation Numbers If nitrogen takes its negative three oxidation number bromine can be 1 or 5. If nitrogen takes its negative three oxidation number bromine can be 1 or 5. NBr 3, N 5 Br 3 NBr 3, N 5 Br 3

41. PWYR – It Gets Worse Selenium and oxygen Selenium and oxygen SeO 2, SeO 3 SeO 2, SeO 3 Phosphorus and fluorine Phosphorus and fluorine PF 3, PF 4, PF 5 PF 3, PF 4, PF 5 Tellurium and iodine Tellurium and iodine TeI 2, Te 5 I 2, Te 7 I 2, TeI 4, TeI 6 TeI 2, Te 5 I 2, Te 7 I 2, TeI 4, TeI 6 Nitrogen and chlorine Nitrogen and chlorine NCl 2, NCl 3, NCl 4, NCl 5, NCl, N 5 Cl 3, N 7 Cl 3 NCl 2, NCl 3, NCl 4, NCl 5, NCl, N 5 Cl 3, N 7 Cl 3