11 grade chemistry others
How many electrons are present in the M-shell of an element with atomic number 20?A) 8B) 6C) 18D) 2
How many electrons are present in the M-shell of an element with atomic number 20?A) 8B) 6C) 18D) 2
1 Answer
Askiitians Tutor Team
To determine the number of electrons in the M-shell of an element with atomic number 20, we need to understand the electronic configuration of the element.
The atomic number 20 corresponds to the element calcium (Ca). The electronic configuration of calcium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
The M-shell refers to the third principal energy level, which includes the 3s, 3p, and 3d subshells. In the case of calcium, the M-shell is completely filled up to the 3p subshell.
The 3s subshell contains 2 electrons, and the 3p subshell contains 6 electrons. Adding these together, we get a total of 2 + 6 = 8 electrons in the M-shell.
Therefore, the correct answer is A) 8.
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