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? group of answer choices a. there are 19 electrons, with 4 shells. there is 1 valence electron. b. there are 19 elecrtons, 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.
The Correct Answer and Explanation is :
The correct answer is a. there are 19 electrons, with 4 shells. There is 1 valence electron.
Explanation:
- Atomic Number and Electrons:
Potassium (K) has an atomic number of 19. The atomic number represents the number of protons in the nucleus of an atom, and since an atom is electrically neutral, the number of electrons will be the same as the number of protons. Therefore, potassium has 19 electrons. - Electron Shells:
The arrangement of electrons in an atom follows the electron configuration, which specifies how electrons are distributed among different energy levels or shells around the nucleus. These shells are labeled as K, L, M, N, or numerically 1, 2, 3, 4, etc.
- The first shell (K) can hold a maximum of 2 electrons.
- The second shell (L) can hold a maximum of 8 electrons.
- The third shell (M) can hold a maximum of 8 electrons.
- The fourth shell (N) can hold a maximum of 1 electron. The electron configuration of potassium is 2, 8, 8, 1. This means that potassium has 4 electron shells: the first shell has 2 electrons, the second shell has 8, the third shell has 8, and the fourth shell has 1 electron. Therefore, potassium has 4 shells in total.
- Valence Electrons:
Valence electrons are the electrons in the outermost shell of an atom, and these electrons are crucial in determining how the atom interacts with other atoms (i.e., chemical reactivity).
- In potassium’s case, the outermost shell (the fourth shell) contains 1 electron. This electron is the valence electron, meaning that potassium has 1 valence electron.
In summary:
- Potassium has 19 electrons.
- These electrons are distributed across 4 electron shells.
- The outermost shell has 1 valence electron, which makes potassium a Group 1 (alkali metal) element in the periodic table.