Answer:
1. Element is Ca
2. 20 electrons
3. 2 valence electrons
4. 4 energy levels
It's a, trust me I'm very good with chemistry
Cu + 4HNO3 ---> Cu(NO3)2 + 2NO2 + 2H2O.
Explanation:
Balancing:
Cu + 4HNO3 ---> Cu(NO3)2 + 2 NO2 + 2H2O.
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