Scientific Understanding

**How do you write nuclear equations?**

This section is built off a previous section of atomic notation in the periodic table lesson toward the beginning of the chemistry course. The atomic notation section shows you how each element is displayed. After you know that you can start putting together many of the elemental displays into an equation. The nuclear equations are very similar to regular chemical equations. Lets look at one below and then dissect it.

86 | Kr → | 58 | Fe | + | 28 | Ne |

36 | 26 | 10 |

The most important things to notice about the nuclear equations are that they have the same yield (arrow) symbol to separate one side of the equation from the other. You can still call them the reactants and the products side but that terminology is not used very often. The most important things about the nuclear equations are to look at the mass numbers and proton numbers. Notice that if you total up all the mass (top numbers) on one side of the equation it equals the total mass on the other side of the equation. This is always true. The same concept works with the protons. That is if you total up all the protons (bottom numbers) on one side of the equation, then they equal the total protons on the other side of the equation. This is always true. However, there are many addition notations that can throw some people. One of those factors is to see coefficients in nuclear equations like the example below.

37 | Cl → | 23 | Na | + | 2 | 7 | Li |

17 | 11 | 3 |

In the example above, you have to remember that each coefficient multiplies both the mass number and the proton number when you are counting them up. So 2 Li has 6 protons total and a total mass of 14. Nuclear equations also use other symbols that may be unfamiliar to you. See examples below.

1 | n | + | 31 | S → | 32 | S |

0 | 16 | 16 |

31 | Si → | 31 | P | + | 0 | e |

14 | 15 | -1 |

In the first example we see the n symbol. The n represents a neutron. In the second example we see an e symbol. The e represents an electron.

**More Examples**: Give the missing information from the nuclear equations.

27 | Al → | 14 | N | + | ||

13 | 7 |

Answer in red

27 | Al → | 14 | N | + | 13 | C |

13 | 7 | 6 |

+ | 40 | Ar → | 62 | Ni | ||

18 | 28 |

Answer in red

22 | Ne | + | 40 | Ar → | 62 | Ni |

10 | 18 | 28 |

**PRACTICE PROBLEMS**: Give the missing information from the nuclear equations below.

87 | Sr → | 65 | Cu | + | 22 | F |

38 | 29 | 9 |

13 | C → | 12 | C | + | 1 | n |

6 | 6 | 0 |

22 | Ne | + | 40 | Ar → | 62 | Ni |

10 | 18 | 28 |

40 | K → | 40 | Ca | + | 0 | e |

19 | 20 | -1 |

78 | Br → | 36 | Cl | + | 2 | 21 | F |

35 | 17 | 9 |