1: Mono- 2: Di- 3: Tri- 4: Tetra- 5: Penta- 6: Hexa- 7: Hepta- 8: Octa- 9: Nona- 10: Deca-

For example: Dinitrogen hexafluoride. The first element is nitrogen and the chemical symbol for nitrogen is N.

For example: Dinitrogen has a the prefix “di-“ which means 2; therefore, there are 2 atoms of nitrogen present. Write dinitrogen as N2.

For example: Dinitrogen hexafluoride. The second element is fluorine. Simply replace the “ide” ending with the actual element name. The chemical symbol for fluorine is F.

For example: Hexafluoride has a prefix of “hexa-“ which means 6; therefore, there are 6 atoms of fluorine present. Write hexafluoride as F6. The final chemical formula for dinitrogen hexafluoride is N2F6.

Sulfur dioxide: SO2 Carbon tetrabromide: CBr4 Diphosphorus pentoxide: P2O5

The chemical symbol for each element can be found on the periodic table. Unlike covalent compounds, Greek prefixes are not used to indicate the number of atoms of each element. You have to balance the charges of the elements to determine the atoms. For example: Lithium oxide is Li2O.

There are only 3 cation polyatomic ions and they are ammonium (NH4+), hydronium (H3+), and mercury(I) (Hg22+). They all have a +1 charge (though, technically, 2 mercury atoms are bonded together, which creates a 2+ charge, with each mercury cation containing a 1+ charge). The rest of the polyatomic ions have negative charges ranging from -1 to -4. Some common ones are carbonate (CO32-), sulfate (SO42-), nitrate (NO3-), and chromate (CrO42-).

All group 1 elements at +1. All group 2 elements are +2. Transition elements will have Roman numerals in parentheses to indicate their charge. Silver is 1+, zinc is 2+, and aluminum is 3+. Group 17 elements are 1-. Group 16 elements are 2-. Group 15 elements are 3-. Remember, when working with polyatomic ions, use the charge of the complete polyatomic ion, rather than the individual ions.

For example: Lithium Oxide. Lithium is a group 1 element and has a +1 charge. Oxygen is a group 16 element and has a 2- charge. In order to balance the 2- charge of the oxygen, you need 2 atoms of lithium; therefore, the chemical formula of lithium oxide is Li2O.

Calcium Nitride: Symbol for calcium is Ca and symbol of nitrogen is N. Ca is a group 2 element and has a charge of +2. Nitrogen is a group 15 element and has a charge of 3-. To balance this, you need 3 atoms of calcium (6+) and 2 atoms of nitrogen (6-): Ca3N2. Mercury(II) Phosphate: Symbol for Mercury is Hg and phosphate is the polyatomic ion PO4. Mercury has a 2+ charge as indicated by the Roman numeral II next to it. Phosphate has a 3- charge. In order to balance them, you will need 3 atoms of mercury (6+) and 2 molecules of phosphate (6-): Hg3(PO4)2.

For example: AgNO3 + NaCl → ? The cations are Ag+1 and Na+1. The anions are NO31- and Cl1-.

Remember to balance the charges when forming new compounds. For example: AgNO3 + NaCl → ? Ag+1 now pairs with Cl1- to form AgCl. Na+1 now pairs with NO31- to form NaNO3.

For example: AgNO3 + NaCl –> ? AgNO3 + NaCl –> AgCl + NaNO3

For example: AgNO3 + NaCl –> AgCl + NaNO3 Count the number of atoms on each side: 1 Ag left, 1 Ag right; 1 N left, 1 N right; 3 O left, 3 O right; 1 Na left, 1 Na right; 1 Cl left, 1 Cl right This equation is balanced because there are equal numbers of atoms on both the left and right side of the equation.

Use “(g)” to indicate a gas, “(s)” to indicate a solid, “(l)” to indicate a liquid, and “(aq)” to indicate a substance dissolved in water.

NiCl2 + (NH4)2S → ? Cations: Ni2+ and NH4+ Anions: Cl1- and S2- Recombine ions to make new products: NiS + NH4Cl Write the equation: NiCl2 + (NH4)2S → NiS + NH4Cl Balance the equation: NiCl2 + (NH4)2S → NiS + 2NH4Cl