Two properties of a star is luminosity and temperature.
Answer:
The mass number of an atom, which is also called the atomic mass number, is the total number of protons and neutrons in an atom,
Explanation:
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Atomic number is equal to the number of electrons in a neutral atom. ... Niobium has an atomic number of 41. ... Determine the number of protons, electrons, and neutrons for each isotope described ... Potassium-41. 19
Answer:
The number of electrons in the outermost shell of an atom is the key to reactivity.
Explanation:
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