Question

question 9 (1 point)
which element has the electron configuration ar4s²?
calcium
argon
sodium
phosphorus

Explanation:

• The electron configuration \([Ar]4s^{2}\) means the element has the electron configuration of argon (\(Ar\), which has 18 electrons) plus 2 more electrons in the \(4s\) orbital.
• The total number of electrons is \(18 + 2=20\).
• The number of electrons in a neutral atom is equal to its atomic number.
• Calcium (\(Ca\)) has an atomic number of 20.
• Argon (\(Ar\)) has an atomic number of 18.
• Sodium (\(Na\)) has an atomic number of 11.
• Phosphorus (\(P\)) has an atomic number of 15.

Answer:

calcium