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Chemical Bonding and Its Types

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  1. Chapter 6 Concept: Types of Chemical Bonds

  2. What is chemical bonding? • Occurs when there is a strong attraction between the valence electrons of one atom and the nucleus of another atom • Formed by rearranging electrons • Atoms have relatively high potential energy as independent particles; but, tend to move toward low potential energy • The way electrons are distributed will determine the type of bond • Most chemical bonds are partly ionic and partly covalent

  3. What is chemical bonding? 3 types of Chemical Bonding • Ionic • Covalent • Metallic Ionic and covalent are the two main types of bonding!!!!

  4. LEQ: What are characteristics of ionic bonding? • Between metal and nonmetal • Electrical attraction (opposite charges hold compounds together). • Smallest particle is an ion • Solid at room temperature; but, brittle • Crystalline lattice structure (repeating patterns of ions)

  5. LEQ: What are characteristics of ionic bonding? • Stronger than covalent bonds • Formula unit • Makes atoms more stable • Lowers potential energy • High melting and boiling points • Good conductors of electricity (in molten state)

  6. LEQ: What are characteristics of ionic bonding? • Ionic bonds (giving or taking of electrons) • Cations • + charge • Lose/give up electrons • metals • Anions • (-) charge • Gain electrons • nonmetals

  7. LEQ: What are characteristics of ionic bonding? • Terms to know • Ionic compound • Compound composed of +/- ions that combine so that they are equal • Formula Unit • Simplest ratio of (+) ions to (–) ions represented by the formula

  8. LEQ: What are characteristics of covalent bonding? • 2 nonmetals share electrons so that both have 8 valence electrons (except H) • Forms molecules • Liquid or gas at room temperature • Illustrated with Lewis Dot • Can be polar or non-polar • Not as strong as/weaker than ionic bonds • Makes atoms more stable by lowering potential energy • Low melting and boiling points

  9. LEQ: What are characteristics of covalent bonding? • Non-polar covalent • Electrons shared equally • No charge created • Occurs between 2 identical atoms • 7 diatomic molecules (HOClBrFIN)

  10. LEQ: What are characteristics of covalent bonding? • Polar Covalent • Electrons not shared equally (tug-of-war) • Electrons spend more time around the more electronegative atom • Slight charges created • (-) charge around the more electronegative atom. • Example: water, HCl (hydrochloric acid)

  11. LEQ: What are characteristics of covalent bonding? • Terms to Know • Molecule • A neutral group of atoms held together by a covalent bond • Molecular compound • Another name for covalent compound • Chemical formula • # of atoms of each element in a compound represented by using symbols and subscripts

  12. LEQ: What are characteristics of covalent bonding? • Terms to Know • Molecular Formula • Types and numbers of atoms in a single molecule • Used for covalent compounds • Example: H2O

  13. LEQ: What are characteristics of covalent bonding? 1. To lower potential energy by making the substance more stable • Attract/repel each other until the distance between the atoms is reached where the repulsion between the like charges equal the attraction of the opposite charges • Atoms have relatively high potential energy as independent particles; but, tend to move toward low potential energy

  14. LEQ: What are characteristics of covalent bonding? 2. To form octet • Octet rule – atoms tend to form compounds (by gaining, losing, or sharing electrons) so that the highest energy level is full (8 electrons in s & p orbitals) • How many more electrons does nitrogen need to satisfy the octet rule if its electron configuration is 1s22s22p3 ?

  15. LEQ: What are characteristics of covalent bonding? • Exceptions to octet rule: • Hydrogen – surrounded up to 2 electrons • Boron – up to 6 electrons • Fluorine, oxygen, and chlorine – more than 8 electrons because they have high electronegativities

  16. LEQ: What are characteristics of ionic and covalent bonding? • Differences in Electronegativity • 0-0.3 (0%-5%)Non-polar covalent • Diatomic molecules • 0.3-1.7 (5%-50%)polar-covalent • HCl • 1.7-3.3 (50% - 100%)ionic • NaCl

  17. Lewis Dot Structures • Uses electron dot to illustrate what a molecule looks like • Electron dot notation • Only shows valence electrons • Symbol of element stands for nucleus and all inner shell electrons • Lewis Dot can show single, double, and triple bonds • If carbon is present, use as central atom. If not, use the least electronegative atom as the central atom. NEVER use hydrogen as central atom.

  18. Lewis Dot Structures • Examples: • IBr • O2 • CH3Br • OF2 • HCL • CF4

  19. What are unique characteristics of Polyatomic Ions? • Polyatomic Ions • A group of covalently bonded atoms that have a charge representing extra electrons • PO43- , NH4+ • Negative – excess of electrons • Positive – shortage of electrons • Has molecular and ionic characteristics

  20. Metallic Bonding • Chemical bonding that results from an attractions between metal atoms and the surrounding electrons • The ions are capable of sliding past one another • Creates the characteristics of being malleable, ductile, and shiny.

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