what is the electron configuration of a calcium atom whose atomic number is 20

1s2 2s2 2p6 3s2 3p6 4s2.

Check it out to make sure this is correct.

1s2 2s2 2p6 3s2 3p6 4s2.

Check it out to make sure this is correct.
Forgot to post the web site where you can check it. http://www.webelements.com/calcium/atoms.html

The electron configuration of a calcium atom with an atomic number of 20 is: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².

The electron configuration of an atom refers to the arrangement of electrons within its electron shells. To determine the electron configuration of a calcium atom (with atomic number 20), we need to follow a specific pattern based on the periodic table.

1. Identify the atomic number of calcium, which is 20. This tells us that a calcium atom has 20 electrons.

2. Starting from the lowest energy level, which is the first shell (n=1), we can place 2 electrons since the first shell can hold up to 2 electrons.

3. Moving to the next energy level, which is the second shell (n=2), we place another 8 electrons, as the second shell can hold up to 8 electrons.

4. Continuing to the third shell (n=3), we place the remaining 10 electrons. However, since calcium only has 20 electrons, we don't need to place all 10. Instead, we place only 2 electrons, which gives us a total of 20 electrons.

The electron configuration of a calcium atom is: 1s2 2s2 2p6 3s2 3p6 4s2.

This notation represents the number of electrons in each energy level (shell) and the subshells (s and p) within those levels. The superscript numbers denote the number of electrons in each subshell.

I hope this explanation helps you understand how to determine the electron configuration of a calcium atom.