Untitled Flashcards Set

• **In a polar covalent bond, two atoms share electrons unequally (think polar opposites)

•** In a non-polar covalent bond, two atoms share the electrons equally

• **Two most common of an examples of a non polar bond, Carbon-Carbon and Carbon-Hydrogen (water fearing)

• **Two most common examples of (unequal sharing) polar covalent bond are Oxygen-Hydrogen and Nitrogen-Hydrogen (water-loving)

• Oxygen- Hydrogen has a total of 8 electrons, 2 shells in inside and 6 on outside. Hydrogen atoms form bond with Oxygen and makes H20.

**Non-Polar Molecules are hydrophobic because they have mostly or entirely nonpolar covalent bonds in its structure (C-C, C-H)

**Ionic Molecules has a charge and can form some kind of attractive force with water

**Polar molecules have one or more polar covalent bonds in it's structure (glucose, glycerol)

In bond that occurs between hydrogen and oxygen has much stronger attraction to shared electrons. Shared electrons spend more time with oxygen and not hydrogen a partial negative charge is put on the oxygen. While the hydrogen will have positive partial charge.

• **Hydrogen Bonds are an attraction that occurs between the partial charge of hydrogen and either a nitrogen or oxygen atom

• ** An attraction that occurs between opposite partial charges.

• In order for a hydrogen bond to occur there needs to be one or more polar covalent bonds in place

• **Vitally important, one of their roles is to help stabilize the 3D structure of different complex molecules like protein and DNA

• **Responsible for most chemical properties of water

• Hydrogen can form both ionic and covalent bonds

• **The attractive force between the partial negative charge oxygen and partial hydrogen positive charge is the hydrogen bond.

• **Partial Negative charge of Nitrogen and Partial positive charge Hydrogen charge form a hydrogen bond

• **Hydrogen Bonds absorb heat energy to make water an effective coolant

• **Ionic Bonds form salt crystals. The formation of salt crystals depend on ionic bonds.

• **An Ionic Bond occurs when there is attraction between oppositely charged Ions

• An atom or a molecule that has a charge is called an Ion. Ions have a charge.

• An Ionic bond always has a positive and negative charge

**Elements in columns 1,2,3 or 7A typically form ionic bonds

1A,- 1+ Cation

2A- +2 Cation

3A- +3 Cation

7A- Pick up one electron so they form -1 charge. So it is a negative charge.

4A,5A,6A- Form Covalent bonds

4A- picks up electrons by forming four covalent bonds

5A- picks up 3 electrons so three bonds

6A- picks up 2 electrons so forms

8A- Already filled valence shell so does not form bonds (unreactive)

3.Van der Waals interaction

• **Are a non-covalent bond is an attraction that occurs between any two closely spaced neutral atoms (fairly weak non covalent bond)

**A covalent bond is formed when atoms share electrons, this takes place when the atoms that form the chemical bond have 4,5,6,7 electrons in the outer shell

A covalent bond is the strongest chemical bond

• Two atoms start sharing electrons when forming covalent bond

• Single Covalent Bond: Shares 1 pair of electrons

• Double Covalent Bond:Shares 2 pairs of electrons

•Triple Covalent Bond: Shares 3 pairs of electrons

**Non-Covalent Bonds are relatively weak but they are far more numerous than covalent bonds.

**They help stabilize complex structures of molecules like proteins and DNA. They also stabilize interaction between those complex molecules.

Non covalent bonds are like proteins.

• **A positive ion charge it is called a Cation

• **A negative ion charge is called a Anion

• Sodium and Chlorine are examples of elements that have ions.

• **Sodium ions lose 1 electron (losing a negative charge) making it a positive 1 charge (Cation)

• **Chlorine picks up 1 electron and has a negative 1 charge and it becomes a negative 1 charge (Anion)

• Sodium has 11 electrons. 2 in the first shell, 8 in the second shell and 1 in the valence shell

** Electrolytes are an Ionic Compund that can form an electric current

• Water makes up 2/3rds of body weight

• **Water is the "universal" solvent, most molecules can dissolve in water

• Solvents are substances that can dissolve solutes, solutes are what are being dissolved within a solvent

**Water is also a very effective lubricant and cushion throughout the body.(i.e the presence of water and fluids in joints.

**Water is also adhesive and cohesive but depends on it's hydrogen formation.

Adhesive means water can stick to other substances,

Cohesive means water can stick to itself

**Water has a high specific heat, water can absorb lots of heat energy.

**Many chemical reactions involve water

In every water molecule there are two covalent bonds, polar covalent bond and an unequal electron sharing.

**Oxygen has a stronger attraction for shared electrons than hydrogen does, which means electrons spend most of time by oxygen.

Oxygen acquires a partial negative charge, while the hydrogen atoms pick up partial positive charge.

**Water is a common reactant. Water can break apart or dissociate to form a hydrogen or hydroxide ion.

**With water having a high specific heat, Water can also store lots of heat energy with a small change in its temperature, and evaporates which can be effective at cooling down (sweating is an example of the body cooling down.)

11. Define solvents, solutes, polar, non-polar, amphipathic, hydrophobic & hydrophilic molecules.

**Solvents are substances that can dissolve solutes,

**Solutes are what are being dissolved within a solvent

Non polar molecules have mostly or entirely non polar covalent bonds.

Polar molecules will have one or more covalent bonds in it's structure

Amphipathic molecules have part of their structure is polar and another part is non polar