1 / 18

Lewis Dot Diagrams and Ions

Lewis Dot Diagrams and Ions. Valence Electrons. The valence electrons are the electrons in the outermost shell of the atom Consider sodium: How many protons? How many neutrons? How many electrons? Draw a Bohr model for sodium. Valence Electrons. Bohr model for sodium:

osmond
Download Presentation

Lewis Dot Diagrams and Ions

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. Lewis Dot Diagrams and Ions

  2. Valence Electrons • The valence electrons are the electrons in the outermost shell of the atom • Consider sodium: • How many protons? • How many neutrons? • How many electrons? • Draw a Bohr model for sodium

  3. Valence Electrons • Bohr model for sodium: • The electron(s) in the highest shell are valence electrons

  4. Lewis Dot Diagram • To draw a Lewis Dot Diagram: • Write the element symbol • Figure out how many valence electrons the atom has • Use dots to represent the valence electrons • Put them in pairs around the 4 sides of the element symbol • For example – try sodium

  5. Lewis Structure Practice • Draw a Lewis Structure for: Calcium Neon Silicon

  6. Ions • Ions are atoms that have the same number of protons, but different numbers of electrons • An ion forms when an atom gains or loses electrons to become more stable • Which group is the most stable? • How many valence electrons does that group have?

  7. Ions • When nonmetals form ions, they tend to gain electrons to fill their valence shell with 8 electrons • When metals form ions, they tend to lose all of their valence electrons

  8. Positive Ion Formation • Atoms in Group 1 lose 1 electron to form ions with a +1 charge • Atoms in Group 2 lose 2 electrons to form ions with a +2 charge • Atoms in Group 13 lose 3 electrons to form ions with a +3 charge • Positive ions are called cations

  9. Negative Ion Formation • Atoms in Group 17 gain 1 electron to form ions with a -1 charge • Atoms in Group 16 gain 2 electrons to form ions with a -2 charge • Atoms in Group 15 gain 3 electrons to form ions with a -3 charge • Negative ions are called anions

  10. Ionic Compounds • When atoms form ionic compounds, an atom transfers one or more of its valence electrons to another atom. • Consider NaCl • Na loses 1 electron to become Na+1 • Cl gains 1 electron to become Cl-1 • The transfer of electrons from one atom to the other causes a more stable arrangement of electrons.

  11. Ionic Compounds • May be made from a metal and a nonmetal - KI • May be made from a metal and a polyatomic ion (Look at your reference table) – LiOH • May be made from two polyatomic ions - NH4C2H3O2

  12. Naming Ionic Compounds • The name of the positive ion stays the same • The end of the element name of the negative ion is changed to an –ide suffix • Chlorine to chloride • Sulfur to sulfide • Phosphorus to phosphide • Polyatomic ions stay as they are written

  13. Ionic Formulas • What ion does sodium form? • Na+1 • What ion does chlorine form? • Cl-1 • What do we change the name of the negative ion to? • Chloride • What is the name of the compound?

  14. Ionic Formulas • What is the formula for the compound made from sodium and chloride ions? • What is the compound made from potassium and iodide ions?

  15. Ionic Formulas Activity • Work in pairs to complete the activity. • Please put all of the shapes back in the bags when you are finished.

  16. Rules for Naming Ionic Compounds • The first element keeps its name. • For monatomic ions, the second element gets the –ide suffix (ending). • Polyatomic ions always keep their names whether they are first or second.

  17. Practice • Name the following ionic compounds: KF MgBr2 Li2S Ca3N2 NaNO3 Mg(OH)2

  18. Exit Ticket • Draw a Lewis Structure for magnesium • Give the charge on a magnesium ion • Give the formula for a compound made from magnesium and bromine • Give the name for CaCl2

More Related