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If an atom has an atomic number of 15 and an atomic mass of 31, how many protons, neutrons and electrons does the atom contain?

Answer 1

This is the isotope phosphorus-31. It has 15 protons, 15 electrons, and 16 neutrons.

The number of protons in the atomic nuclei of any element is its atomic number; in a neutral atom, the number of electrons is equal to the number of protons; the mass number of an atom is the total of the protons and neutrons in the nucleus; the mass number varies because the number of neutrons varies; isotopes are named according to their mass numbers.

Accordingly, the atomic number of this element is 15, its electron count is 15, and its mass number (atomic number minus mass number) is 16.

Phosphorus-31, with atomic number 15, is this isotope.

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Answer 2

Jose Ayala

The composition of the atom with an atomic mass of 31 and an atomic number of 15 is as follows: 15 protons, 15 electrons, and 16 neutrons.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.