1 / 18

Chemical bonding

Chemical bonding. Objectives: Can you identify ionic and covalent bonds? Can you name chemical compounds?. Properties of Ionic Compounds. They are crystalline solids at room temperature (like salt) They have high melting points

lotta
Download Presentation

Chemical bonding

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chemical bonding Objectives: Can you identify ionic and covalent bonds? Can you name chemical compounds?

  2. Properties of Ionic Compounds • They are crystalline solids at room temperature (like salt) • They have high melting points • They conduct electricity when they are dissolved in water or when they are in molten stat e(heated up so high they turn into liquid) • They are made up of metals and nonmetals

  3. Ionic compounds • What holds ionic compounds together? • The difference in charges between the ions. • Opposites attract. • How are ions formed? • When electrons are transferred from one element to another. • The atom becomes an ion because the number of protons and electrons are no longer equal creating charges.

  4. Conductivity • Ionic compounds are non-conductors but they are conductors when in aqueous solution. • What does that mean? • When ionic solids are melted or dissolved, they break into ions. • The electrically charged ions are then free to move. • Their motion conducts electricity • Strong vs Weak Electrolytes • What are electrolytes? • Conductivity videos

  5. Ionic Bonding • If an element gains electrons, the charge is negative • If an element loses electrons, the charge is positive.

  6. Review periodic table • Each group has a specific charge. • Groups are columns. Look at your periodic table and label the charges associated with the group.

  7. Ionic bonds • Involves electrostatic attraction between opposite charges of atoms. • Cations • Positively charged atoms. • Anions • Negatively charged atoms. • Ends in -ide • Cations and Anions come together to form ionic compounds • Examples: • Sodium + Chlorine  Sodium Chloride • Na++ Cl- NaCl

  8. Ionic Bonds continued • What if the charges are different? • Example: Lithium (1+) and Oxygen(2-) • Criss-cross the numbers and bring them down. • Why? • Because the charges are different in ratio 1:2, criss-crossing will cancel the charges out to make a stable compound. • Transition elements with different charges have their charges in parenthesis like Iron (II) Fe2+ and Iron (III) Fe3+ , or Copper (II) Cu2+ and Copper (III) Cu3+

  9. Molecular/Covalent bonding • Instead of using charges to bond, covalent bonds share electrons. • Also called a molecular compound. • They can have unequal amount of electrons • This causes polarity • One side has more electronegativity • Polarity • Depends on shape of the molecule and orientation of bonds • Nonpolar substances have an equal amount of sharing and there is no pulling • Electronegativity – The tendency of an atom to attract electrons toward itself

  10. Characteristics of covalent compounds • Gases, liquids, and brittle solids (like Carbon) at room temperature • Low melting points • Do not conduct electricity when dissolved in water • Made up of nonmetals • Covalent compounds video

  11. Properties of Molecular compounds Appearance of pure molecular compounds • Most molecular compounds are liquids or gases at room temperature • Some are solids and have crystalline structure and are brittle. • Some are solids and have a powder-like appearance and are soft.

  12. Chemical Bonds • Why do atoms bond? (phet stimulation) • Stability • Interactions/attractions • Chemical bond – electrical attractions that hold atoms together and lower the energy state of the system (they become more stable)

  13. Covalent bonding nomenclature • If a compound has two or more nonmetals, they are written with prefixes of the number of that atom. • Example: • CO2 Carbon Dioxide • N2H4DinitrogenTetrahydride • 1 – Mono (for the second element) 6 - Hexa • 2 – Di 7 - Hepta • 3 – Tri 8 – Octa • 4 – Tetra 9 - Nona • 5 – Penta 10 – Deca • If the next word after the prefix starts with the vowel the “a” in the prefix is dropped. Example: Hexafluoride vs. Hexoxide, not Hexaoxide.

  14. Polyatomic ions • Groups of atoms that are covalently bonded together and have a charge on the whole group. • They function like any other single atom ion and combine with any charged ion. • Examples: • Sulfate SO42- • Carbonate CO32- • Nitrate NO3- • Ammonium NH4+

  15. Polyatomic ions continued • Most polyatomic ions have different amount of hydrogens oxygens and they are named according to how much more or how much less hydrogen or oxygen the polyatomic ion has. • Chlorate vs. Chlorite vs. Perchlorate vs. Hypochlorite (there will never be a hypochlorate or perchlorite) • -ate = the median amount of oxygen atoms • -ite = one less oxygen than –ate • Hypo= one less oygen than –te • Per = one more oxygen than -ate • Hypo-, -Ite, -Ate, Per- • Sufate vs. Sulfate. • Nitrate vs. Nitrite

  16. Polyatomic ion practice

  17. Acids Nomenclature • Elements that are combined with Hydrogen become binary acids. • HCl, HBr, HF • Nomenclature: Hydro+(element)-ic + acid. • Hydrochloric acid • Hydrofluoric acid • What is Bromine + Hydrogen? • Polyatomic ions that combine with Hydrogen become ternary acids • HSO4, HClO3 • Nomenclature: Ends with –ous or –ic + acid • -ate-ic, -ite-ous • Sulfate SO42- with Hydrogen  H2SO4 (Sulfuric acid) • Nitrite NO3- with H+  HNO3 (Nitrous acid) • What is Nitrate + Hydrogen?

  18. Acids nomenclature practice

More Related