LEDS - Bond Formation and Breaking (PDF)

 BOND FORMATION Prepared by: Ms. Erika Valdez KEYWORDS: Lewis Dot Structure Octet rule Electrostatic force  O B J EC TIVES 1 2 Draw the Understand Lewis electron the principles dot structure of che...

 BOND FORMATION Prepared by: Ms. Erika Valdez KEYWORDS: Lewis Dot Structure Octet rule Electrostatic force  O B J EC TIVES 1 2 Draw the Understand Lewis electron the principles dot structure of chemical of elements/ bonding. compounds What are the ways of determining the number of valence electron of an atom? e- configuration: 1s² 2s² 2p⁶ 3s² 3p⁵ Group no. in the periodic table: 7 Valence e- = 7 LEWIS ELECTRON DOT STRUCTURE (LEDS) A diagram that describes the chemical bonding between atoms in a molecule. Dots are used to represent the valence electrons in atoms and molecules. Gilbert Newton Lewis LEWIS The nucleus and inner shells of the element are represented by the ELECTRON elements symbol. DOT The outermost shell and the valence STRUCTURE electrons are represented by the dots. (LEDS) Remember that in writing the LEDS, you have to put dots on each side of the element before making a pair. Chlorine 1s² 2s² 2p⁶ 3s² 3p⁵ Valence e- = 7 Hydrogen 1s¹ Valence e- = 1 Boron 1s² 2s² 2p¹ Valence e- = 3 Nitrogen 1s² 2s² 2p³ Valence e- = 5 Magnesium 1s² 2s² 2p⁶ 3s² Valence e- = 2 Carbon 1s² 2s² 2p² Valence e- = 4 Oxygen 1s² 2s² 2p⁴ Valence e- = 6  OCTET Which of the following elements reached full valency? RULE Electron Number of Atom valence - refers to the tendency Configuration electrons of atoms to prefer to C 1s2 2s2 2p2 4 have 8 electrons in the O 1s2 2s2 2p4 6 Ne 1s2 2s2 2p6 8 valence shell, often Cl 1s2 2s2 2p6 3s2 3p5 7 resembling that of the Ar 1s2 2s2 2p6 3s2 3p6 8 nearest noble gas K 1s2 2s2 2p6 3s2 3p6 4s1 1 OCTET RULE ATOM VALENCE ELECTRONS C 4 O 6  Lone pairs Bonding pairs  Try this! ATOM VALENCE ELECTRONS C 4 Cl 7  Try this! ATOM VALENCE ELECTRONS C 4 H 1  Try this! ATOM VALENCE ELECTRONS N 5 H 1  3 RULES TO ACHIEVE OCTET RULE 1 2 3 Sharing of Metal may Non-metal electrons with lose electron may gain other atoms. to form electron to cation. form anion. 1.) Sharing of electrons with other atoms  2. Metal may lose 3. Non-metal may e- to form cation gain e- to form anion Cation - an atom losing an electron becomes positively charged Anion - an atom gaining an electron becomes negatively charged How does the arrangement of electrons in an atom influence its bonding behavior? Noble Gas Atoms with full valence shells, like noble gases, are less reactive. Atoms with nearly full valence shells such as halogens are more reactive Halogen because they tend to gain electrons. Atoms with nearly empty valence shells such as alkali metals are more reactive Alkali because they tend to lose electrons. Metal  RE VIE W 1 2 What does Lewis Define octet rule. electron dot structure represent?  Guide Questions Guide Questions 1. What is the basic structure of an atom? An atom consists of a nucleus with positively- charged protons and neutral neutrons, orbited by negatively- charged electrons ELECTROSTATIC INTERACTION attractive or repulsive forces between charged particles ELECTROSTATIC INTERACTION electrons and protons create these interactions. Guide Questions 2. How do electron shells influence atomic bonding? Electrons in outer shells can be attracted to other atoms’ nuclei, leading to overlapping shells and shared electrons, forming chemical bonds. Guide Questions 3. What is electronegativity and how does it affect chemical bonds? Electronegativity is an atom’s ability to attract electrons. High differences in electronegativity lead to unequal sharing of electrons, forming ionic bonds. Guide Questions: Why do atoms form chemical bonds? Atoms bond to achieve stability by sharing or transferring electrons, resulting in molecules that make up everything. Is any of the element an electronically charged atom? When does an element become electronically charged and radioactive? ION an atom or group of atom either loses an electron or gains an extra electron. Cation Anion An atom losing an An atom gaining an electron becomes electron becomes positively charged. negatively charged.