Chemistry Review: Atoms ➲ Made up of a nucleus containing protons and neutrons and orbitals...

Chemistry Review: Atoms➲ Made up of a nucleus containing protons

and neutrons and orbitals containing electrons

➲ Outermost electrons are known as valence electrons.

Isotopes

• Atoms that have the same number of protons, but have a different number of neutrons.

Ions➲ Ion: Valence electrons are lost

or gained in order to have a full outer shell. This results in a charge.

➲ Positive ion: cation.➲ Negative ion: anion.

Intramolecular Bonds➲ Ionic Bonds: A force of attraction between

a cation and an anion➲ Ex. NaCl

Intramolecular Bonds➲ Covalent Bonds: neither atom is willing to

give up electrons so the electron pairs are shared

➲ ex. H2 (g) , CH4 (g)

Intramolecular Bonds➲ Double and triple bonds can result if 2 or 3

pairs are shared.ex. O2, N2, CH2CH2

Electronegativity➲ Electronegativity: The ability for an atom

to attract electrons➲ Non-polar covalent bond:

➲ the atoms involved have similar electronegativities, so the electrons are shared equally.

➲ (ex. C-H).

Electronegativity➲ Polar covalent bonds: the atoms

involved have different electronegativities so there is uneven sharing of electrons. This results in a separation of charge.

➲ (ex. O-H)

Polar Covalent Molecules➲ If the molecule is asymmetrical and has a

polar covalent bond, the molecule will also be polar.

➲ ex. H2O, CH3OH

Non-polar Covalent Molecules

• A molecule has non polar covalent bonds OR because of the symmetrical arrangement of polar covalent bonds.

Hydrogen Bonds➲ The partial charges on polar

covalent molecules result in attraction between molecules.

➲ Ex. Hydrogen bonds➲ electronegative atom and a

hydrogen atom bonded to either nitrogen, oxygen, or fluorine.

Organic Compounds➲ Organic compounds: “chemicals of life”,

contain a lot of Carbon ex. C6H12O6

➲ Hydrocarbons: only contain C and H, ex. CH4

Water➲ Water is inorganic (no Carbon) but is an

important chemical to life

Water➲ It is polar covalent➲ Like dissolves like: Other polar molecules

are hydrophilic and will dissolve, ➲ Nonpolar molecules/functional groups are

hydrophobic and will not

1. How many valence electrons does fluorine have?a. What kind of an ion would fluorine form? b. How many valence electrons would the fluorine ion have?

2. What is the difference between an ionic bond and a covalent bond?

3. If oxygen always takes electrons from other atoms, does it have high electronegativity or low electronegativity?

4. Hydrogen has low electronegativity. Flourine has high electronegativity. What would the charges look like around a H-F molecule?

5. Explain why water is good at dissolving polar molecules