Question

identify of each element with the election configuration by its chemical symbol
{ar} ar 4s² →
{ar} 4s² 3d¹⁰ 4p⁶ →
1s² 2s² →

Explanation:

Step1: Recall electron configuration rules

Electron configurations are written based on the Aufbau principle, Pauli exclusion principle, and Hund's rule. For elements, we can use noble - gas core notation.

Step2: Analyze \([Ar]4s^{1}\)

The noble - gas core \([Ar]\) represents the electron configuration of argon (\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}\)). Adding \(4s^{1}\) gives the electron configuration of potassium (\(K\)). The atomic number of \(K\) is \(19\) (\(18\) electrons from \([Ar]\) plus \(1\) from \(4s^{1}\)).

Step3: Analyze \([Ar]4s^{2}3d^{10}4p^{5}\)

The \([Ar]\) core has \(18\) electrons. \(4s^{2}\) contributes \(2\) electrons, \(3d^{10}\) contributes \(10\) electrons, and \(4p^{5}\) contributes \(5\) electrons. The total number of electrons is \(18 + 2+10 + 5=35\). The element with atomic number \(35\) is bromine (\(Br\)).

Step4: Analyze \(1s^{2}2s^{2}\)

The total number of electrons is \(2 + 2=4\). The element with atomic number \(4\) is beryllium (\(Be\)).

Answer:

\([Ar]4s^{1}\to\) Potassium (\(K\)); \([Ar]4s^{2}3d^{10}4p^{5}\to\) Bromine (\(Br\)); \(1s^{2}2s^{2}\to\) Beryllium (\(Be\))