Q
QuestionChemistry

Potassium (K) has an atomic number of 19. How many electrons does this element have? How many electron shells? How many valence electrons are present? A. There are 19 electrons, with 4 shells. There is 1 valence electron. B. There are 19 electrons, with 3 shells. There are 8 valence electrons. C. There are 19 electrons, with 4 shells. There are 2 valence electrons. D. There are 19 electrons, with 3 shells. There is 1 valence electron. Asked by Looneytunness^4623 • 09 / 12 / 2023
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Answer

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Step 1

\text{Number of electrons} = \boxed{19}
The number of electrons in an atom is equal to its atomic number. Therefore, potassium (K) with an atomic number of 19 has 19 electrons.

Step 2

\text{Number of electron shells} = \boxed{4}
To find the number of electron shells, we need to determine the highest value of the principal quantum number (n) for any of the electrons. The first shell (n= 1) can hold up to 2 electrons, and subsequent shells can hold up to 8 electrons each. For potassium, the 19 electrons are distributed as follows: - The 1st shell can hold up to 2 electrons, and since potassium has an atomic number of 19, the 1st shell is full. - The 2nd shell can hold up to 8 electrons, and the next 10 electrons of potassium (from atomic number 11 to 20) fill this shell. - The 3rd shell can also hold up to 8 electrons, and the next 8 electrons of potassium (from atomic number 21 to 28) fill this shell. - The 4th shell starts filling with the 19th electron of potassium. Therefore, potassium has 4 electron shells.

Final Answer

Based on the above analysis, the correct answer is: A. There are 19 electrons, with 4 shells. There is 1 valence electron.