Answer:
Magnesium nucleus will attract the electrons more toward it and therefore, shrinking the size of the atom. Magnesium atom is smaller than Calcium atom because Calcium has more electron ( 20e− ) which will occupy more energy levels ( n=4 for Calcium versus n=3 for Magnesium)
Answer:
It is reactive because it has to gain an electron to have a full outermost energy level.
Explanation:
The electron configuration of oxygen is 1s2,2s2 2p4.
Oxygen is in group six in the periodic table so it has six electrons in its valence shell. This means that it needs to gain two electrons to obey the octet rule and have a full outer shell of electrons (eight).
B. Share Electrons.
Hope this helps.
<span>d. A catalyst will be used up in the reaction is wrong,
amount of catalyst should not change</span>
Considering the definition of percentage by mass, the mass percentage of CaCO₃ is 68.59%.
<h3>What is mass percentage</h3>
The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.
In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.
The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

<h3>Mass percentage of CaCO₃</h3>
In this case, you know:
- mass of CaCO₃: 2.62 grams
- mass of limestone: 3.82 grams
Replacing in the definition of mass percentage:

<u><em>mass percentage= 68.59 %</em></u>
Finally, the mass percentage of CaCO₃ is 68.59%.
Learn more about percentage by mass:
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