Question

34
what is the ground - state electron configuration of as? (1 point)
ar4s²3d¹⁰4p³
kr4s²3d¹⁰4p³
kr4s²4d¹⁰4p³
ar4s²4d¹⁰4p³

Explanation:

• Atomic number of As: Arsenic (As) has an atomic number of 33.
• Noble - gas core: Argon (\([Ar]\)) has 18 electrons. The remaining \(33 - 18=15\) electrons are filled in the \(4s\), \(3d\), and \(4p\) orbitals.
• Filling order: According to the Aufbau principle, the filling order is \(4s<3d < 4p\). The \(4s\) orbital can hold 2 electrons (\(4s^{2}\)), the \(3d\) orbital can hold 10 electrons (\(3d^{10}\)), and the \(4p\) orbital for As (which has 5 valence electrons after filling \(4s\) and \(3d\)) will have 3 electrons (\(4p^{3}\)).

Answer:

$$ \boxed{[Ar]4s^{2}3d^{10}4p^{3}} $$