Part 1: Potassium, and Rubidium.
Part 2: Calcium has 20 protons and 20 electrons because the atomic number for calcium is 20 and that determines how many protons there are and in an atom, the number of protons is the same number of electrons. Calcium has about 20 neutrons. I got the number of Neutrons by subtracting the mass number(40.078) and the atomic number(20), I got 20.078. Round to the nearest whole number because you cannot have half or partial neutron. So, Calcium has 20 protons, 20 electrons, and 20 neutrons,
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It well be 9025 because it will dissolve in 0.8 hcl soluiton
Copper (II) Carbonate + Heat yields copper (II) oxide and carbon dioxide
Molecular Equation: CuCo3 + heat > CuO + CO2
Answer: option B. closer to oxygen in the case of CO2
Explanation: