Presentation on theme: "On the periodic table: The horizontal rows are called ____________ The vertical columns are called ___________ Identify elements by their properties and."— Presentation transcript:
On the periodic table: The horizontal rows are called ____________ The vertical columns are called ___________ Identify elements by their properties and placement on the periodic table.
Links: What Holds a Molecule Together? Ionic Bonding: Interactive Tutorial
- Ionic Bonds Ionic Bonds You and a friend walk past a market that sells apples for 40 cents each and pears for 50 cents each. You have 45 cents and want an apple. Your friend also has 45 cents but wants a pear.
Atoms like to have a filled outer shell of electrons. Sometimes, by transferring electrons from one atom to another, electron shells are filled. The atom that gives away an electron will take a positive charge, and the receiving atom will have a negative charge. The charged atoms or ions will be attracted to each other, and form bonds.
- Ionic Bonds Ions and Ionic Bonds Ionic bonds form as a result of the attraction between positive and negative ions.
Ionic compounds and ionic bonding When metals react with non-metals, electrons are transferred from the metal atoms to the non-metal atoms, forming ions. The resulting compound is called an ionic compound.electronsionsionic compound Consider reactions between metals and non-metals, for example sodium + chlorine sodium chloride magnesium + oxygen magnesium oxide calcium + chlorine calcium chloride In each of these reactions, the metal atoms give electrons to the non-metal atoms, so that the metal atoms become positive ions and the non-metal atoms become negative ions. There is a strong electrostatic force of attraction between these oppositely-charged ions, called an ionic bond. The animation shows ionic bonds being formed in sodium chloride, magnesium oxide and calcium chloride. electrostatic
- Ionic Bonds Properties of Ionic Compounds In general, ionic compounds are hard, brittle crystals that have high melting points. When dissolved in water or melted, they conduct electricity.
Some atoms like to share electrons to complete their outer shell. Like this oxygen atom. It needs 2 electrons to follow the 2/8/8 rule. In this case to make water, you would need 2 hydrogen atoms. By sharing electrons the hydrogen atom is also able to complete it’s electron shell. Hydrogen bonds are primarily covalent bonds and a regular covalent bond is very strong. Oxygen
- Covalent Bonds How Covalent Bonds Form The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons.
- Covalent Bonds How Covalent Bonds Form The oxygen atom in water and the nitrogen atom in ammonia are each surrounded by eight electrons as a result of sharing electrons with hydrogen atoms.
- Covalent Bonds How Covalent Bonds Form An oxygen molecule contains one double bond, while a carbon dioxide molecule has two double bonds. A nitrogen molecule contains one triple bond.
Covalent compounds - simple molecules Covalent bondsCovalent bonds form between non-metal atoms. Each bond consists of a shared pair of electrons, and is very strong. Covalently-bonded substances fall into two main types:electrons 1.simple molecules, andmolecules 2.giant covalent structures. Simple molecules These contain only a few atoms held together by strong covalent bonds. An example is carbon dioxide (CO 2 ), whose molecules contain one atom of carbon bonded with two atoms of oxygen.atom A molecule of carbon dioxide Hydrogen chloride, ammonia, methane, chlorine, and water are also examples of simple molecules with covalent bonds. All these substances have very strong bonds between the atoms, but much weaker forces holding the molecules together. When one of these substances melts or boils, it is these weak 'intermolecular forces' that break, not the strong covalent bonds. This means that simple molecular substances are gases, liquids or solids with low melting points and low boiling points.
On the Inside BY YOURSELF complete BOTH sides of the “On the Inside” worksheet. You do NOT have to draw the Oxygen Atom GO ON
Website Click the link below & then click LAUNCH http://www.pbslearningmedia.org/resource/ls ps07.sci.phys.matter.theatom/the-atom/ Now try this more challenging website & click on ATOM BUILDER ACTIVITY http://www.pbs.org/wgbh/aso/tryit/atom/# **Hint: Use “The Atom Builder Guide” links at bottom of page for help
Interactive Periodic Table Game CLICK ON PICTURE:
___Ductile ___Malleable Able to be pulled into a long wire c d Able to be hammered or rolled into a shape ___Brittleg Easily broken and is not able to be molded or shaped ___ Conductor of electricity k Allows electricity to flow freely
___ Conductor of heat ___Dull Allows heat to flow freely l n Not shiny ___Softm Not hard ___Shiny i Lusterous
___ high boiling point ___ High melting point Boils at a high temp. so is usually a liquid at room temperature h j Melts at high temp. so is usually a solid at room temperature ___ Semiconductor f Will carry electricity only under certain conditions ___Opaque a Not clear or transparent
___Density ___Reactive b e Will quickly & easily combine with other elements D=M÷V, determines is it will sink or float