Valence Electrons and Bonding Lesson 3.04 Valence Electrons and Bonding

Vocabulary Terms Valence Electron- an electron of an atom, located in the outermost shell. Bond – something that holds together. Octet Rule/Rule of Eight - chemical rule of thumb that states that atoms tend to combine in such a way that they each have eight electrons in their valence shells. Ionic Bonding - A chemical bond that results from electrostatic attraction between positive and negative ions. It is due to transfer of electrons between a metal and a nonmetal.

Vocabulary Terms Covalent Bonding - A chemical bond in which electrons are shared between two atoms. The sharing of electrons between two nonmetals. Electronegativity - tendency for an atom to attract a pair of electrons that it shares with another atom. Polar Covalent Bond- a covalent bond where atoms have unequal attraction for the shared electrons. Non-polar Covalent Bonds – a covalent bond in which the atoms have an equal attraction to the shared electrons.

Valence Electrons Electrons in the outermost shell or highest energy level are called valence electrons. Ex: Carbon – 1s2 2s2 2p2 Highest energy level is second level with four electrons(2s2, 2p2), therefore the number of valence electron for carbon is equal to 4.

Valence Electrons

Valence Electrons Valence electrons = number of dots(Lewis Dot structure)

Ionic Bonding Transfer of electron/s between a metal(+ion) and a nonmetal(-ion)

Ionic Bonding Ex: NaCl

Ionic Bonding – Let’s Practice Mg + Cl 2) Al + O

Covalent Bonding Sharing of electrons between 2 nonmetals(- ion)

Covalent Bonding Ex: CH4 Sharing of electrons between 4 atoms of Hydrogen and 1 atom of carbon to form CH4.

Covalent Bonding- Let’s Practice H + Cl F + F

Polar Covalent Bond HF F has a higher electronegativity than H, the atom with greater electronegativity is able to take the electrons from the other atom making it a negative ion and the other atom as a positive ion. A Polar Covalent bond has an uneven distribution of the charge, slightly negative on one end and slightly positive on the other end.

Non Polar Covalent Bond H2 2 atoms of Hydrogen having the same electronegativity. Both atoms have the same strength of attraction for the electrons and are equally shared. A Non polar covalent Bond have an equal attraction for the shared electrons.