Vocab :)

2. Vocab :) •Covalent bond- Chemical bond in which two atoms share a pair of valence electrons. • Molecule- Neutral group of atoms that are joined together by one or more covalent bonds. •Polar Covalent bond- A covalent bond in which electrons are not shared equally.

3. Sharing electrons A covalent bond is a chemical bond in which two atoms share a pair of valence electrons. When two atoms share one pair of electrons, the bond is called a single bond. The electrons in the outermost shell are the valence electrons (The electron that is associated with the atom)- the electrons on an atom that can be gained or lost in a chemical reaction.

4. Example using Chlorine For example, two chlorine atoms could both achieve stable structures by sharing their single unpaired electron as in the diagram. The fact that one chlorine has been drawn with electrons marked as crosses and the other as dots is simply to show where all the electrons come from. In reality there is no difference between them. The two chlorine atoms are said to be joined by a covalent bond. The reason that the two chlorine atoms stick together is that the shared pair of electrons is attracted to the nucleus of both chlorine atoms.

5.  Covalent Bonds  A covalent bond forms when bound atoms have low energy than of widely seperated atoms. All of this was discovered by a man named G.N. Lewis, who first introduced the idea that two electrons could be shared between two atoms by a link in 1916.

6. Molecules of Elements  Different Molecules A molecule is a neutral group of atoms that are joined together by one or more covalent bonds. A chemical formula can be used to describe the molecules of an element. The element hydrogen is a great example. - Hydrogen has the chemical formula of H₂. The subscript 2 indicates that there are two atoms in the molecule of hydrogen.

7. (continued)  Molecule Lots of people think there is a difference between a molecule and a compound. The truth is, a compound is a type of molecule.Ifthe types of atoms are different from each other, a compound is formed. Not all molecules are compounds, since some molecules, such as hydrogen gas or ozone, consist only of one element or type of atom.

8. Multiple Covalent bonds When two atoms share three pairs of electrons, the bond is called a triple bond. When two atoms share two pairs of electrons, the bond is called a double bond. Double and triple bonds are the names of the bonds multiplying. Ex. Two Chlorine atoms could both achieve stable structures by sharing their single unpaired electron. The two atoms are joined by covalent bonds.

9. (Continued) Ionic bonds hold atoms together through electrostatic forces. Covalent bonds operate through an entirely different means: the sharing of electrons. By sharing electrons, two atoms can mutually complete their valence shells to become more stable. A molecule is a collection of atoms held together by covalent bonds. For example, below, two hydrogen atoms, each with a single electron, can share their electrons to form a covalent bond and create the diatomic hydrogen molecule. In this molecular state, both individual hydrogen atoms attain the noble gas configuration of Helium. Note: the simplest way to represent molecules is to use a Lewis Dot structure, which is what you see in the diagram below. We will explain how to draw Lewis structures later on in this section.

10. Unequal sharing of electrons  Periodic Table Generally, elements on the right of the periodic have a greater attraction for electrons than elements on the left have(except for noble gases). And, generally, elements at the top of a group have a greater attraction for electrons than the elements at the bottom of a group have.

11. Polar covalent bonds In a molecule of an element, the atoms that form covalent bonds have the same ability to attract an electron. Share electrons are attracted equally to the nuclei of both atoms. In a molecule of a compound, electrons may not be shared equally. A covalent bond in which electrons are not shared equally is called a Polar covalent bond. The electrons are not transferred from one atom to the other they are in an ionic bond. Instead, some outer electrons merely spend more time in the vicinity of the other atom. The effect of this orbital distortion is to induce regional net charges that hold the atoms together.  Polar Covalent Bond

12. Polar and Nonpolar Molecules If a molecule has only two atoms, it will be polar. The type atoms in a molecule and its shape are factors that determine whether a molecule is polar or nonpolar. Atoms in some molecules is such that one end of the molecule has a positive electrical charge and the other side has a negative charge. If this is the case, the molecule is called a polar molecule, meaning that it has electrical poles. Otherwise, it is called a non-polar molecule. Whether molecules are polar or non-polar determines if they will mix to form a solution or that they don't mix well together.  Nonpolar covalent bond

13. (Continue) A good example for a nonpolar covalent bond would be, Oxygen and Oxygen. Two oxygen atoms can both achieve stable structures by sharing two pairs of electrons as in the diagram. The double bond is shown conventionally by two lines joining the atoms. Each line represents one pair of shared electrons.

14. http://www.britannica.com/EBchecked/topic/141012/covalent-bondhttp://www.britannica.com/EBchecked/topic/141012/covalent-bond http://academic.brooklyn.cuny.edu/biology/bio4fv/page/polar_c.htm http://www.chemguide.co.uk/atoms/bonding/covalent.html http://www.chem.latech.edu/~upali/chem481/p01244.htm http://academic.brooklyn.cuny.edu/biology/bio4fv/page/polar_c.htm http://www.britannica.com/EBchecked/media/92140/Polar-covalent-bond-In-polar-covalent-bonds-such-as-that http://www.webchem.net/notes/chemical_bonding/covalent_bonding.htm Works Cited!

15. Answers (: B. A chemical bond in which two atoms share a valence of electrons. C. Both A &B B. When bond atoms have LOW energy. Neutral group of atoms joined together. Molecules are parts of an element. A compound is 2 or more elements together. D. Have more than 1 electrons. A. Electrostatic forces. C. The sharing of electrons. The way electrons are shared. B. Electron associated with the atom.