WAEC - Chemistry (2023 - No. 38)
Which of the following elements has its valence electrons in the s-orbital?
Aluminum
Phosphorus
Sodium
Carbon
คำอธิบาย
Sodium is an alkali metal, and its atomic number is 11. This means that it has 11 electrons, and its electron configuration is \(1s^2 2s^2 2p^6 3s^1\). The valence electrons are the electrons in the outermost shell, which in this case is the 3s orbital.