Chemical Bonds

Class activity Each team will receive a card describing a chemical element. Each team will make a posters(Helpers) You have 5minutes for this activity!!!!(Time trackers) You will have to present the team work and score points for your team We will have to read careful over the card and as a team came out with a poster describing: Borh Model Lewis model Number of protons Number of electrons Numbers o neutrons Valence electrons One interesting fact about the element

Electron shells Atomic number = number of protons= number of electrons Electrons are placed on energy levels or electron shells fallowing a specific rule Electron shells configuration determine how an atom behaves when it encounters other atoms

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

What & Why We review structure of an atom and the relationships among protons, neutrons and electrons. We analyze pictograms We apply concepts about ratio and decimals. We interpret data. To understand that the structure of an atom affect the chemical interactions between the atoms . To practice how to inference based on information from pictures and graph and connect of your knowledge about of matter. In order to analyze the sub-particles of an atom. In order to generate patterns.

DISCOVER ACTIVITY Team #1 Activity #1 Team#2 Activity #2 Fallow the steps for each activity You have 10 minutes Stay focus! Complete your work! Be ready to answer questions and take points for your team! Teams will take points when everyone in the group is ready!

Why are electrons important? Elements have different electron configurations different electron configurations mean different types of bonding. We learn that the structure of an atom determine the how chemical compounds are formed. When atoms bond more complex molecules are form and different type of matter will form

What are Chemical bonds An attraction between atoms! An attempt of atoms to fill electron shells fallowing the octet rule! We will learn to draw and model ionic and covalent bonds in order to have a deeper understanding of chemical bonds between atoms.

Ion= electrically charged atom Ions are atoms whose number of electrons does not equal the number of protons. Atoms with more electrons than protons are called anions and have a negative electrical charge Atoms with more protons than electrons are cations and have a positive charge.

Formation of Ions from Metals Metals lose electrons to match the octet rule Positive ions form when the number of electrons are less than the number of protons =CATIONS

Formation of Sodium Ion Sodium atom Sodium ion Na  – e  Na + 2-8-1 2-8 ( = Ne) 11 p+ 11 p+ 11 e- 10 e- 0 1+

Formation of Magnesium Ion Magnesium atom Magnesium ion  Mg  – 2e  Mg2+ 2-8-2 2-8 (=Ne) 12 p+ 12 p+ 12 e- 10 e- 0 2+

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

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+

Formation of Ions from Nonmetals Nonmetals accept electrons to match the octet rule Negatives ions form when the number of electrons are more than the number of protons =ANIONS

Fluoride Ion     1 - : F  + e : F :     2-7 2-8 (= Ne) unpaired electron octet     1 - : F  + e : F :     2-7 2-8 (= Ne) 9 p+ 9 p+ 9 e- 10 e- 0 1 - ionic charge

IONIC BOND bond formed between two ions by the transfer of electrons

Ionic Bond Between atoms of metals and nonmetals A chemical bond formed through an electrostatic attraction between two oppositely charged ions. Bond formed by transfer of electrons Examples; NaCl, CaCl2, K2O

Ionic bond – electron from Na is transferred to Cl (Na+) becomes cation and the Cl becomes (Cl-) anion, charged particles or ions.

COVALENT BOND bond formed by the sharing of electrons

Covalent Bond Between nonmetallic elements of similar electronegativity. Formed by sharing electron pairs Examples; O2, CO2, C2H6, H2O, SiC

Covalent Bonds

when electrons are shared equally COVALENT BONDS when electrons are shared equally H2 or Cl2

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

when electrons are shared but shared unequally COVALENT BONDS when electrons are shared but shared unequally H2O

End of the lesson assessment Question #1Using the example of a salt molecule analyzed in class, construct a model of a water molecule using the chemical formula H2O.Be sure to label the atoms and the chemical bonds. Ocean water contains 3 tablespoons of salt so is not suitable to drinking. Design a solution you could use to separate the salt from the water. Include the tools you would use and how you would measure or determine that you separated the salt. If necessary use your Ipad to see lesson vocabulary PPt

Homework Helpers please take the homework from the back table Please use the class online website to access the lesson concepts