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 magnetic quantum number (m_l) for a 3d orbital can be -2, -1, 0, 1, or 2.

The maximum number of electrons in the n=2 shell is 2(2^2) = 8.

The maximum number of electrons in a shell is given by 2n^2. For n=3, it is 2(3^2) = 18.

The maximum number of electrons in a shell is given by 2n^2. For n=5, it is 2(5^2) = 50.

The maximum number of electrons in a shell is given by 2n^2. For n=4, it is 2(4^2) = 32.

The maximum number of electrons in a subshell is given by the formula 2(2l + 1). For l = 2, it is 2(2*2 + 1) = 10.

The maximum number of electrons in a shell is given by 2n^2. For n=2, this is 2(2^2) = 8.

The maximum number of electrons in a shell is given by 2n^2. For n=5, it is 2(5^2) = 50.

A p subshell can hold a maximum of 6 electrons.

A single orbital can hold a maximum of 2 electrons, with opposite spins.

A single p-orbital can hold a maximum of 2 electrons.

The maximum number of electrons in a subshell is given by the formula 2(2l + 1). For l=2, this gives 2(2*2 + 1) = 10.

The maximum number of electrons in a subshell is given by the formula 2(2l + 1). For l = 2, this gives 2(2*2 + 1) = 10.

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 maximum number of electrons in a shell is given by the formula 2n^2. For n=3, it is 2(3^2) = 18.

For l=1, the number of orbitals is given by 2l + 1 = 3.

The number of orbitals in a subshell is given by 2l + 1. For l = 3, it is 2*3 + 1 = 7.

The magnetic quantum number m_l can take values from -l to +l. For l = 3, m_l can be -3, -2, -1, 0, +1, +2, +3, giving a maximum value of 3.

The principal quantum number n for the 5d subshell is 5.

The ground state of a hydrogen atom corresponds to n=1.

Chlorine has an atomic number of 17, and its outermost electrons are in the n=3 shell.