Answer:
The mass number (A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. The mass number is different for each different isotope of a chemical element.
Answer: The values can be converted from one unit to other unit still keeping the meaning same. We use the number 273 (273.15 exactly) to convert from Celsius to Kelvin and vice versa. . ... Kelvin temperature scale: In Kelvin temperature scale, the zero point is shifted from freezing point of water to the absolute zero point.
Explanation:
Basically the answer
The correct answer would be D. Ca^2+ has 18 electrons. This is because 2+ means that 2 electrons have been removed, and Ca starts out with 20 electrons. As 20 - 2 = 18 electrons, D is the correct answer.
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