Bell Work(Plickers)  Which option contains only compounds? A. H 2 O, H 2 O 2, H 3 O, CO 2 B. Na, NaCl, Pb, C 6 H 12 O 6 C. NH 3, KNO 3, Hg, Ne D. Au, Ni, Cu, Fe

Element Quiz 12/4/14 Know Elements Atomic # Symbol Name STUDY

Student Learning Objectives  SPI Recognize that all matter consists of atoms.  SPI Differentiate between a mixture and a compound.  SPI Use the periodic table to determine the properties of an element.  Describe Covalent bonding.  Describe Metallic bonding. TOC:  58. Covalent and Metallic Bonds  HW - Friday- Word Wall Crossword Puzzle due

Covalent and Metallic Bonds  Brain Pop!

Covalent and Metallic Bonds Explain how covalent bonds form. Explain how metallic Explain how metallic bonds form. bonds form.

Covalent and Metallic bonds  Covalent bonds usually form between atoms of nonmetals.  A covalent bond forms when atoms share one or more pairs of electrons.

 Substances containing covalent bonds consist of individual particles called molecules.  Most molecules are composed of atoms of two or more elements.

Covalent compounds and molecules  A molecule is the smallest particle into which a covalently bonded compound can be divided and still be the same compound.  (H 2 O is still water even if there is just one molecule of it)

 One way to represent atoms and molecules is to use electron-dot diagrams. An electron-dot diagram shows only the valence electrons in an atom.

Covalent Bonds Interactive covalent bond activity

Covalent bonds – share electrons Both atoms use the same electrons

Ammonia – NH 3 Share electrons to have a full outer level N H HH NH 3

Properties of covalent bonds Substances that have covalent bonds tend to have:  Low melting point  Low boiling point  Are brittle in the solid state  (examples: oxygen has a low boiling point, wood is brittle and breaks when bent)

A metallic bond is formed by the attraction between positively charged metal ions and the electrons in the metal.  Bonding in metals is a result of the metal atoms being so close to one another that their valence levels overlap. This overlapping allows valence electrons to move throughout the metal.

Properties of metallic bonds  Metallic bonding gives metals their particular properties:  Electrical conductivity  Malleability  Ductility Review with your table group what these three properties are; and if they are physical or chemical properties?

Electrical Conductivity  Metallic bonds allow metals to conduct electrical current. When you turn on a lamp, electrons move within the copper wire that connects the lamp to the outlet. The electrons that move are the valence electrons.  These electrons are free to move because the electrons are not connected to any one atom.

Ductility and Malleability Ductility is the ability to be drawn into wires.  Example – copper can be made into wires for electrical cords. Malleability is the ability to be hammered into sheets.  Example – is aluminum can be pounded into thin sheets. Moving electrons maintain the metallic bonds no matter how the shape of the metal changes. Which means metal objects can be bent without being broken.