Module 9: Chemical Bonding

Chemical bond

is the attractive force that holds two or more atoms together.

Compounds

The formation of chemical bonds between atoms creates

Covalent bonds and ionic bonds

Chemical bonds are the attractive forces that hold atoms together in the form of compounds. A chemical bond is formed when electrons are shared between two atoms. There are two types of chemical bonds:

Electron dot diagram, Lewis diagram/structure

is a representation of the valence electrons of an atom that uses dots around the symbol of the element.

Valence electron

Lewis Structure: The number of dots represents the number of ____ of an atom.

Bond pair

A pair of electrons that is shared between two atoms is called a

Lone pair

A pair of electrons that is not shared between two atoms is called a

Octet Rule

The atoms that participate in covalent bonding share electrons in a way that enables them to acquire a stable electron configuration, or full valence shell. This means that they want to acquire the electronic configuration of the noble gas of their row.

Hydrogen

only requires 2 electrons to have a full valence shell since it only needs to be like Helium (He).

3rd period

Elements on the ______ of the periodic table and below can actually have more than 8 electrons around them. They have extra space to allow for the extra electrons.

Simple Covalent Bond

• one in which the shared pair of electrons come from both atoms.

• Example: H2, Cl2, O2, N2

Single bond (Ethane)

single shared pair of electrons

Double bond (Ethene)

2 shared pair of electrons

Triple bond (Etyhne)

3 shared pair of electrons

Methane (CH4)

is a colorless, odorless gas commonly used as a fuel – the main component of natural gas. It is a hydrocarbon and, therefore, organic in nature. It is also one of the carbon originating gases that play a major role in the greenhouse effect.

Coordinate Covalent Bond

is one in which the shared pair of electrons come from only one atom.

• SO2

• CO

Ionic Bond

involves the complete transfer of electrons from one atom to another. This transfer results in the formation of positively-charged bonds (CATIONS) and negative ions (ANIONS).

Cation

An atom that loses one or more valence electrons gains a positive charge

Anion

the atom which gains the electrons becomes negative charges

Polar Covalent Bond

If the atoms differ in their attraction for electrons, ____ will be formed. Water is an example of a molecule

Carbon Dioxide

considered the most dangerous greenhouse gas, and at the same time, it is one of the most essential requirements for life to exist on our planet.

Electronegativity

The attraction of electrons to the nucleus of an atom is a very important property of atoms

Bond polarity

The difference in electronegativity between bonded atoms determines the _____, which is determined by the relative difference in electronegativity between two atoms that are joined together by a chemical bond.

Dipole

results from an unequal distribution of the electron pair in the bond between the atoms.

Non-polar covalent bond

• this bond exists when two or more electrons are equally shared between atoms of the same or almost the same electron negativities and the electric charges in the molecule are symmetrically distributed.

• an electronegativity difference of 0 to 0.4

Polar Covalent Bond

• exists when the two atoms in a covalent bond have different electron negativities and the larger the electronegativity of an element, the more strongly an atom of the element attracts electrons.

• an electronegativity difference of 0.5 to 1.5

Ionic

an electronegativity difference of above 1.5 is characteristic of an