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Balancing chemical equations, etc.

1. Use the periodic table to write the balanced chemical equation for the reactions of elemental calcium atoms and diatomic elemental nitrogen atoms. (Please explain how to use the periodic table to solve this problem and show work - I really want to learn how this works!).

3. An ion has 12 protons, 13 neutrons, and 10 electrons.
What is its charge? Consult the periodic table and write the symbol of the ion. (Why do I have to consult the table? Can't I just subtract?)

2. The diameter of an atom is approximately 10210 m. The diameter of an atomic nucleus is about 10215 m. What is the ratio of the atomic diameter to the nuclear diameter? (Please show formula and work).

Solution Preview

ANSWER:
3Ca + N2 → Ca3N2

Note: You need to consult the periodic table to know the corresponding charges of calcium and nitrogen when they form compounds. For example, based on the periodic table, calcium belongs to Group II. Hence, it forms a cation with +2 charge, that is, Ca+2. On the other hand, nitrogen belongs to Group V in the periodic table. Hence, it forms anion with -3 charge, that is, N-3. When Ca+2 and N-3 react, cross-over rule is applied, hence the formula of the compound is Ca3N2:
Ca+2 + ...

Solution Summary

The expert examines balancing chemical equations for the periodic table. The ratio of the atomic diameter to the nuclear diameter are determined.

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