Science Flashcards

Front 1

Steps to writing a formula

Back 1

1) write the symbols of the element or poly-atomic ions in the compound next to each other
2) Write the oxidation numbers of the elements or poly-atomic ions over the symbols
3) Cross over the #s of the charges but not the + or -- sign, and write the numbers as subscripts
4) Write the formula of the compound, showing the subscripts but not the charges

Front 2

Remember!!!

Back 2

A subscript of 1 is NEVER written, if the oxidation numbers are the same, no subscript needs to be written, if a ploy-atomic ion is involved, parenthesis are written around the poly-atomic ion only if you add a subscript in writing the formula

Front 3

Naming Binary Compounds

Back 3

1) Name the first element in a copmlound as usuakl
2) Name the second element, then drop the ending of the name
3) Add "ide" to the name of the second element

Front 4

Naming Poly-atomic Compounds

Back 4

If a compound has more than 2 elements in it -- look on the oxidation sheeft for the pol-atomic ion that is involved & name the compound using the name of the poly-atomic ion

Front 5

Finding Molecular and Formula Mass

Back 5

1) Write the chemical formula for the compound
2) Count the # of atoms of each element in the compound
3) Look up the atomic mass of each of these elements using the Periodic Table
4) Find the total mass that each element contributes to the compound. To do this, multiply the atomic mass of each element by the # of atoms of that element in the compound
5) Add the total mass of each element in the compound
(see next card)

Front 6

Example

Back 6

Na CO
2 Na x 23 amu= 46
1 C x 12 amu= 12
30 x 16 amu= +48
_____
106 amu

Front 7

Please write in a 2 after Na and a 3 after CO (subscripts)

Back 7

Please write in a 2 after Na and a 3 after C) (subscripts)