1 / 9

3.2 How Atoms Combine

3.2 How Atoms Combine. Objectives: Differentiate between Compounds & Molecules Differentiate between Covalent & Ionic Bonds Comprehend how ions form and how they aid in bonding Utilize the pH scale. Compounds.

lilka
Download Presentation

3.2 How Atoms Combine

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. 3.2 How Atoms Combine Objectives: Differentiate between Compounds & Molecules Differentiate between Covalent & Ionic Bonds Comprehend how ions form and how they aid in bonding Utilize the pH scale

  2. Compounds • Compounds: Substance that is composed of atoms of two or more different elements that are chemically combined. • Ex: Table Salt (NaCl), Water (H2O) • Compounds usually have properties different than their elements.

  3. Covalent Bonds • Atoms like to be stable and have their outer electron shells full. • Covalent Bonds: Atoms share electrons and hold the atoms together. • CH4=

  4. Molecules • Molecules: Composed of two or more atoms held together by covalent bonds. • Molecules have no charge because the number of electrons and protons are equal. • All compounds are molecules, but not all molecules are compounds.

  5. Ions & Ionic Bonds • Not all atoms bond by sharing electrons, they can give up and receive each others valence electrons. • This only happens when there are 4 or less valence electrons. • The atom that loses its electrons is called a positive ion, while the atom that gains the electron is called the negative ion.

  6. Ions & Ionic Bonds • Ionic Bond: Positive & Negative Ions attract each other like magnets. • In a chemical formula, the positive ion is always written before the negative ion • Ex: Na+Cl- • Ionic bonds are stronger than covalent bonds.

  7. Chemical Reactions • Chemical Reaction: The change of one or more substances into a new substance. • Chemical Reactions have reactants and products. • Ex. 2H2 + O2 2H2O • Reactants: Are the “ingredients”; H & O • Product: The end result; Water • Reactants  Products

  8. Mixtures • Mixture: A combination of two or more components that retain their identities. • Heterogeneous: A mixture’s components are easily recognizable. • Ex. Sand & Water • Homogeneous: A mixture’s components cannot be distinguished, although they each still retain their properties. • Ex. Salt & water • MIXTURES ARE ABLE TO BE SEPARATED!

  9. pH Scale • Measures acids & bases. • Acids • Substance that produces hydrogen ions (H+) • Has a pH value between 1 (strong acid) – 7 (weak acid) • Bases • Substance that produces hydroxide ions (OH-) • Has a pH value between 7 (weak base) – 14 (strong base) • A pH of 7 is neutral. Water is neutral.

More Related