Chlorine ion (Cl-) has gained an electron, resulting in the configuration 1s2 2s2 2p6.

Oxygen has 8 electrons. The electronic configuration is 1s2 2s2 2p4.

Sodium has 11 electrons, and its configuration is 1s2 2s2 2p6 3s1.

Sodium ion (Na+) has lost one electron, resulting in the configuration 1s2 2s2 2p6.

Chlorine (Cl) has 17 electrons, so its configuration is 1s2 2s2 2p6 3s2 3p5.

Iron (Fe) has the configuration [Ar] 4s2 3d6.

Oxygen has 8 electrons, and its electronic configuration is 1s2 2s2 2p4.

Chloride ion has gained one electron, making its configuration 1s2 2s2 2p6 3s2 3p6.

The element with atomic number 12 is magnesium (Mg), and its electronic configuration is [Ne] 3s2.

The element with atomic number 15 is phosphorus (P), and its electronic configuration is [Ne] 3s2 3p3.

Chlorine (Cl) has the configuration 1s2 2s2 2p6 3s2 3p5.

The element with atomic number 20 is Calcium, which has the configuration [Ar] 4s2.

The element with atomic number 26 is iron (Fe), and its electronic configuration is [Ar] 4s2 3d6.

Copper (Cu) has the configuration [Ar] 4s2 3d9.

Iron (Fe) has 26 electrons, and its electronic configuration is [Ar] 4s2 3d6.

Nitrogen has 7 electrons, and its electronic configuration is 1s2 2s2 2p3.

The potassium ion (K+) loses one electron, resulting in the configuration 1s2 2s2 2p6.

Sodium ion (Na+) has lost one electron, resulting in the configuration 1s2 2s2 2p6.

The maximum number of electrons in an energy level is given by the formula 2n^2. For n=3, it is 2(3^2) = 18.

The total number of electrons is 36 (from Kr) + 2 (from 5s2) + 10 (from 4d10) + 5 (from 5p5) = 53.

The element with the configuration 1s2 2s2 2p6 3s2 3p1 is Aluminum (Al).

The configuration corresponds to Krypton (Kr), which has 36 electrons.

The configuration 1s2 2s2 2p6 3s2 3p6 is incorrect as it exceeds the maximum number of electrons in the 3rd shell.

The configuration 1s2 2s2 2p6 corresponds to Neon, a noble gas.

The configuration [Kr] 5s2 4d5 represents Molybdenum (Mo), a transition metal.

Nitrogen has the electronic configuration 1s2 2s2 2p3, which means it has a half-filled p subshell.

Chromium (Cr) has an electronic configuration of [Ar] 4s1 3d5, which means it has an incomplete d subshell.

Calcium (Ca) has an atomic number of 20, and its electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s2.

Bromine (Br) has the electronic configuration ending in 4p5, corresponding to atomic number 35.

The element with the configuration [Kr] 5s2 4d10 5p5 is Astatine (At), which has atomic number 85.