Balanced or Unbalanced? Write a “B” for Balanced and a “U” for Unbalanced. 11.CH4 + O2 à CO2 + 2 H2O
12. NaBr + CaF2 à NaF + CaBr2
13. 4 Fe + 3 O2 à 2 Fe2 O3

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.

Amixture that has two or more substances that are spread out evenly is called a. compound b. heterogeneous c. substance d. homogeneous

Which of the following isotopes has the same number of neutrons as phosphorus-31?