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How many electrons are present in an atom in which the first and second shells and the 3s subshell are filled? Name the element.
2. Atoms and the Periodic Table
Electron Arrangements
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Write the electron arrangement for the following element:Calcium (Z = 20)
A
2-2-6-2-6-2
B
2-8-8-2
C
2-16-2
D
2-8-8-1
E
1-2-2-8-2
Verified step by step guidance1
Identify the atomic number of calcium, which is 20. This means calcium has 20 electrons to arrange.
Understand that electrons fill orbitals in a specific order based on increasing energy levels, following the Aufbau principle.
Begin filling the electron orbitals: Start with the 1s orbital, which can hold 2 electrons, so the first two electrons go into 1s.
Next, fill the 2s orbital with 2 electrons, followed by the 2p orbital, which can hold 6 electrons. This accounts for 10 electrons so far.
Continue by filling the 3s orbital with 2 electrons, then the 3p orbital with 6 electrons, and finally, place the remaining 2 electrons in the 4s orbital, resulting in the electron configuration: 2-8-8-2.
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