1. Bell Ringer
1) Which nucleus below belongs to the element on the right? (red = proton, yellow = neutron) a) b) c) d)

2. 2) Your friend stands on a scale and proclaims that his mass is 170 pounds. You answer: a) That is not your mass. Your mass is how much space you take up. 170 pounds is your weight b) Your mass is equal to the pressure of gravity pulling on you. That is why your mass is 170 pounds.

3. 3) There are four elements associated with life – they make up 90% of all living things. Which answer lists them? a) Carbon, Nitrogen, Phosphorus, Magnesium b) Carbon, Oxygen, Hydrogen, Silicon c) Nitrogen, Beryllium, Hydrogen, Oxygen d) Hydrogen, Oxygen, Nitrogen, Carbon

4. The pictures below best represent:
a) neutrons b) isotopes c) protons d) atoms

5. Chemical Bonds

6. Still Chemistry... Chemical compounds are found all around us.
Do you recognize these common chemical compounds?
- NaCl =
- C12H22O12 =
- CH2CH3OH =
- NaOCl =
Salt
Sucrose (sugar)
Mouthwash
Bleach

7. Still Chemistry...
The chemical and physical properties of elements change when they become compounds.
Sodium (Na) is a solid that reacts explosively with water.

8. Still Chemistry...
The chemical and physical properties of elements change when they become compounds.
Sodium (Na) reacts explosively with water.
Chlorine (Cl) is a poisonous gas

9. Still Chemistry...
The chemical and physical properties of elements change when they become compounds.
Sodium (Na) reacts explosively with water.
Chlorine (Cl) is a poisonous gas
But, together, they make table salt (NaCl) =

10. Still Chemistry...
Most atoms are not stable in their natural state, so they react with other atoms (forming compounds) to become more stable.

11. Still Chemistry...
Most atoms are not stable in their natural state, so they react with other atoms (forming compounds) to become more stable.
Chemical compounds are formed by atoms joining together.
These atoms are held together by chemical bonds.

12. Still Chemistry...
Most atoms are not stable in their natural state, so they react with other atoms (forming compounds) to become more stable.
Chemical compounds are formed by atoms joining together.
These atoms are held together by chemical bonds.
Bonding is all about the electrons!

13. Atom – the smallest unit of matter “indivisible”
Helium
atom

14. electron shells Atomic number = number of Electrons
Electrons vary in the amount of energy they possess, and they occur at certain energy levels or electron shells.
Electron shells determine how an atom behaves when it encounters other atoms

15. Electrons are placed in shells according to rules:
The 1st shell can hold up to two electrons, and each shell thereafter can hold up to 8 electrons.

16. Octet Rule = atoms tend to gain, lose or share electrons so as to have 8 electrons
C would like to
N would like to
O would like to
Gain 4 electrons
Gain 3 electrons
Gain 2 electrons

17. Why are electrons important?
Elements have different electron configurations
different electron configurations mean different levels of bonding

19. Electron Dot Structures
Symbols of atoms with dots to represent the valence-shell electrons
H He:
          
Li Be  B   C   N   O  : F  :Ne :
       
          
Na Mg  Al  Si  P S :Cl  :Ar :
       

20. Chemical Bond A force of attraction that holds two atoms together
Has a significant effect on chemical and physical properties of compounds
involves the valence electrons
Valence Electrons – the electrons in the outermost energy level of an atom
This Lithium
Atom has one
valence electron

21. Learning Check A. X would be the electron dot formula for
A. X would be the electron dot formula for
1) Na 2) K 3) Al
 
B  X  would be the electron dot formula
1) B 2) N 3) P

22. CONSIDER EIGHT A HAPPY NUMBER FOR ATOMS!
The Octet Rule
Atoms will combine to form compounds in order to reach eight electrons in their outer energy level.
Atoms with less than 4 electrons tend to lose electrons.
Atoms with more than 4 electrons tend to gain electrons.
Be aware that there are some exceptions!
CONSIDER EIGHT A HAPPY NUMBER FOR ATOMS!

23. Chemical bonds: an attempt to fill electron shells
Ionic bonds –
Covalent bonds –
Metallic bonds
What can you describe about each of these
bonds just by looking at the name?

24. IONIC BOND bonds formed between two ions by the transfer of electrons
Which different groups or families
of elements will most-likely
interact to create these types
of bonds?

25. Formation of Ions from Metals
Ionic compounds result when metals react with nonmetals
Metals lose electrons to match the number of valence electrons of their nearest noble gas
Positive ions form when the number of electrons are less than the number of protons
Group 1 metals  ion 1+
Group 2 metals  ion 2+
Group 13 metals  ion 3+

26. Formation of Sodium Ion
Sodium atom Sodium ion
Na  – e  Na +
( = Ne)

27. Formation of Magnesium Ion
Magnesium atom Magnesium ion 
Mg  – 2e  Mg2+
(=Ne)

28. Some Typical Ions with Positive Charges (Cations)
Group 1 Group 2 Group 13
H+ Mg2+ Al3+
Li+ Ca2+
Na+ Sr2+
K+ Ba2+

29. Learning Check A. Number of valence electrons in aluminum
1) 1 e ) 2 e- 3) 3 e-
B. Change in electrons for octet
1) lose 3e ) gain 3 e ) gain 5 e-
C. Ionic charge of aluminum
1) ) ) 3+

30. Solution A. Number of valence electrons in aluminum 3) 3 e-
B. Change in electrons for octet
1) lose 3e-
C. Ionic charge of aluminum
3) 3+

31. Learning Check Give the ionic charge for each of the following:
A. 12 p+ and 10 e-
1) 0 2) 2+ 3) 2-
B. 50p+ and 46 e-
1) 2+ 2) 4+ 3) 4-
C. 15 p+ and 18e-
2) ) 3- 3) 5-

32. Fluoride Ion     1 - : F  + e : F :     2-7 2-8 (= Ne)
unpaired electron octet
   
: F  e : F :
   
(= Ne)
ionic charge

33. Ionic Bond
Between atoms of metals and nonmetals with very different electronegativity
Bond formed by transfer of electrons
Produce charged ions all states. Conductors and have high melting point.
Examples; NaCl, CaCl2, K2O

34. Ions from Nonmetal Ions
In ionic compounds, nonmetals in 15, 16, and 17 gain electrons from metals
Nonmetal add electrons to achieve the octet arrangement
Nonmetal ionic charge:
3-, 2-, or 1-

36. Ionic Bonds: One Big Greedy Thief Dog!

37. 1). Ionic bond – electron from Na is transferred to Cl, this causes a charge imbalance in each atom. The Na becomes (Na+) and the Cl becomes (Cl-), charged particles or ions.

39. COVALENT BOND bond formed by the sharing of electrons http://www

40. Covalent Bond
Between nonmetallic elements of similar electronegativity.
Formed by sharing electron pairs
Stable non-ionizing particles, they are not conductors at any state
Examples; O2, CO2, C2H6, H2O, SiC

41. Covalent Bonds

42. Bonds in all the polyatomic ions and diatomics are all covalent bonds

43. when electrons are shared equally
NONPOLAR COVALENT BONDS
when electrons are shared equally
H2 or Cl2

44. 2. Covalent bonds- Two atoms share one or more pairs of outer-shell electrons.
Oxygen Atom
Oxygen Atom
Oxygen Molecule (O2)

45. when electrons are shared but shared unequally
POLAR COVALENT BONDS
when electrons are shared but shared unequally
H2O

46. Polar Covalent Bonds: Unevenly matched, but willing to share.

47. - water is a polar molecule because oxygen is more electronegative than hydrogen, and therefore electrons are pulled closer to oxygen.

48. METALLIC BOND bond found in metals; holds metal atoms together very strongly

49. how the electrons do not just stay with one ion
Metallic Bond
A force of attraction between a positively charged metal ion and the electrons in a metal
Many metal ions pass along many electrons
Many properties of metals, such as conductivity, ductility, and malleability, result from the freely moving electrons in the metal
Usually occurs between atoms of metals
Al3+ - - -
Notice
how the electrons do not just stay with one ion - - - - - - - - - - -

50. Metallic Bond Formed between atoms of metallic elements
Electron cloud around atoms
Good conductors at all states, lustrous, very high melting points
Examples; Na, Fe, Al, Au, Co

51. Metallic Bonds: Mellow dogs with plenty of bones to go around.

52. Ionic Bond, A Sea of Electrons

53. Metals Form Alloys Metals do not combine with metals. They form
Alloys which is a solution of a metal in a metal.
Examples are steel, brass, bronze and pewter.

54. Results of Bonding Molecule
A neutral group of two or more non-metal atoms held together by covalent bonds
Type:
Diatomic - molecules consisting of two atoms of the same element bonded together
Examples:
H2, F2, O2, N2
Compound
A pure substance composed of two or more different elements (atoms) that are chemically combined
Examples:
CO, NO2, NaCl
What would you call something that has
characteristics of both?

55. Molecule, Compound, or Both?
Nitrogen
Cl2
Chlorine
Nitrogen Dioxide
NO2
CO2
Carbon Dioxide O2
Oxygen
CH4
Methane H2
Hydrogen NO
Nitric Oxide
H2O
Water

57. THE END!
(or is it?)