Atomic Structure and Electron Configuration - AP Chemistry

2 unpaired electrons. Carbon's 2p subshell has 2 electrons, both unpaired by Hund's rule.

$1s^2 2s^2 2p^6$. Neon has 10 electrons filling through the 2p subshell completely.

$1s^2 2s^2 2p^6 3s^2 3p^6$. Argon has 18 electrons completely filling through the 3p subshell.

Orientation of an orbital. Describes which specific orbital within a subshell the electron occupies.

0 to $n-1$. For a given $n$, the azimuthal quantum number ranges from 0 to $n-1$.

8 electrons. The $n=2$ level has 2s and 2p subshells: $2 + 6 = 8$ electrons total.

5 valence electrons. Nitrogen is in group 15, so it has 5 valence electrons.

n. The principal quantum number indicates the energy level or shell.

32 electrons. The $n=4$ level can hold $2n^2 = 2(4)^2 = 32$ electrons total.

9 orbitals. The $n=3$ level has s, p, and d subshells: $1 + 3 + 5 = 9$ orbitals.

$1s^2 2s^2 2p^6 3s^2 3p^6$. Calcium loses 2 electrons to form $Ca^{2+}$, giving argon's configuration.

Azimuthal quantum number ($l$). The $l$ value determines whether an orbital is s, p, d, or f type.

6 valence electrons. Oxygen is in group 16, so it has 6 electrons in its outermost shell.

Neutrons = Mass number - Atomic number. Mass number includes both protons and neutrons, so subtract protons to get neutrons.

$1s^2$. Helium has 2 electrons, both filling the 1s orbital.

5 orbitals. The d subshell contains 5 degenerate orbitals.

$1s^2 2s^2 2p^6 3s^1$. Sodium has 11 electrons, filling through 3s with one electron.

Neutral charge (0). Neutrons are electrically neutral particles in the nucleus.

Pauli Exclusion Principle. Each electron must have a unique set of four quantum numbers.

Spherical. All s orbitals have spherical symmetry around the nucleus.

14 electrons. The f subshell has 7 orbitals, each holding 2 electrons maximum.

2 electrons. Maximum capacity per orbital due to Pauli Exclusion Principle.

Hund's Rule. Maximizes unpaired electrons before pairing to minimize electron-electron repulsion.

10 electrons. Neon's atomic number is 10, so neutral atoms have 10 electrons.

$1s^2 2s^2 2p^6$. Fluoride ion gains one electron, achieving neon's electron configuration.

$1s^2 2s^2 2p^6 3s^2 3p^6 4s^1$. Potassium has 19 electrons, with the last electron in the 4s orbital.

$1s^2 2s^2 2p^6 3s^2 3p^4$. Sulfur has 16 electrons, with 4 electrons in the 3p subshell.

Chlorine (Cl). The configuration $[Ne] 3s^2 3p^5$ indicates 17 total electrons, which is chlorine.

17 electrons. Chlorine's atomic number is 17, so neutral atoms have 17 electrons.