Bell Ringer Draw the Molecule & give the Formula for: – Carbon and 2 Sulfurs – Hydrogen, Oxygen, and Chlorine – Carbon, two Chlorines, 2 Fluorines – Phosphorus, Hydrogen, Sulfur

Molecular Compounds: Formulas & Naming Ch 6.3b - Covalent Bonds

Describing Molecular Compounds What information do the name and formula of a molecular compound provide? – Ionic Bonds (Ionic Compounds) -

Describing Molecular Compounds What information do the name and formula of a molecular compound provide? – Ionic Bonds (Ionic Compounds) - Name – Type of elements in the compound Formula – Ratio/Number of atoms of each element in the compound.

Describing Molecular Compounds Covalent Bonds (Molecular Compounds) – Name & Formula - the type and number of atoms in a molecule of the compound.

Naming Molecular Compounds Naming Order: Step 1: – Element farthest to the left  named 1 st. Most Metallic Elements in the same group  more metallic element is closer to the bottom of the group. Name does not change! (just like in ionic) – Formulas are written same way – Example: Sulfur is named before chlorine  SCl 2

Naming Molecular Compounds Exception: Oxygen & Halogens – Oxygen comes 2 nd when combined with lower-electronegativity halogens (Group 17) – Example: ClO 2 (electronegativity: Cl = 3.0; O = 3.5)

Naming Molecular Compounds Step 2: – Second element  “ide” ending (like the anion in an ionic compound) Examples: –Chlorine  chloride –Oxygen  oxide

mono - one di - two tri - three tetra - four penta - five hexa - six hepta - seven octa - eight nona - nine deca - ten Naming Molecular Compounds Step 3: – Add prefixes to elements names to specify the number of atoms of each element in the compound.

Naming Molecular Compounds Prefixes: mono - one di - two tri - three tetra - four penta - five Example: N 2 O  Dinitrogen monoxide N 4 O 5  Tetranitrogen pentoxide

Naming Molecular Compounds CO  Carbon monoxide CO 2  Carbon dioxide SO 10  Sulfur decaoxide Exception to Step 3– – Only one atom of the 1 st element = NO PREFIX!

Naming Molecular Compounds More Examples: N 2 Cl 5  – Dinitrogen pentachloride N 2 O 5  – Dinitrogen pentoxide P 5 Cl 6  – Pentaphosphorous hexachloride SO 10  – Sulfur decaoxide

Writing Molecular Formulas Step 1: – Write the element symbols (in order) Step 2: – Prefixes values  subscripts No prefix = 1 atom (no subscript) –Only applies to 1 st element in the formula

Writing Molecular Formulas Examples: – Diphosphorus Pentoxide  P 2 O 5 – Silcon Dioxide  SiO 2 – Carbon Tetrachloride  CCl 4 – Trineptunium Octoxide  Np 3 O 8

You Try Give the formula for: – Oxygen Difluoride  – Phosphorus Tribromide  – Trisilicon Tetranitride  Give the Name for: – NO 2  – N 2 O 3  – SO 3 

You Try - Answers Give the formula for: – Oxygen Difluoride  OF 2 – Phosphorus Tribromide  – Trisilicon Tetranitride  Give the Name for: – NO 2  – N 2 O 3  – SO 3 

You Try - Answers Give the formula for: – Oxygen Difluoride  OF 2 – Phosphorus Tribromide  PBr 3 – Trisilicon Tetranitride  Give the Name for: – NO 2  – N 2 O 3  – SO 3 

You Try - Answers Give the formula for: – Oxygen Difluoride  OF 2 – Phosphorus Tribromide  PBr 3 – Trisilicon Tetranitride  Si 3 N 4 Give the Name for: – NO 2  – N 2 O 3  – SO 3 

You Try - Answers Give the formula for: – Oxygen Difluoride  OF 2 – Phosphorus Tribromide  PBr 3 – Trisilicon Tetranitride  Si 3 N 4 Give the Name for: – NO 2  Nitrogen Dioxide – N 2 O 3  – SO 3 

You Try - Answers Give the formula for: – Oxygen Difluoride  OF 2 – Phosphorus Tribromide  PBr 3 – Trisilicon Tetranitride  Si 3 N 4 Give the Name for: – NO 2  Nitrogen Dioxide – N 2 O 3  Dinitrogen Trioxide – SO 3 

You Try - Answers Give the formula for: – Oxygen Difluoride  OF 2 – Phosphorus Tribromide  PBr 3 – Trisilicon Tetranitride  Si 3 N 4 Give the Name for: – NO 2  Nitrogen Dioxide – N 2 O 3  Dinitrogen Trioxide – SO 3  Sulfur Trioxide