Question

how many core electrons does sn have?
46
50
4
36

Explanation:

Step1: Determine Sn's atomic number

Tin (Sn) has an atomic number of 50, so it has 50 electrons.

Step2: Find Sn's electron configuration

The electron configuration of Sn is $[Kr] 4d^{10} 5s^2 5p^2$. The noble gas core here is Kr, which has 36 electrons. But wait, core electrons are the electrons in the inner shells, excluding the valence electrons. Wait, no—wait, the electron configuration of Sn: atomic number 50. So electron configuration is $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^2$. Wait, no, the correct noble gas notation is $[Kr] 4d^{10} 5s^2 5p^2$. Kr has 36 electrons. Then the valence electrons are in the 5s and 5p orbitals: 2 + 2 = 4 valence electrons. So core electrons = total electrons - valence electrons = 50 - 4 = 46. Wait, but let's check again. Wait, the electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p². So the core electrons are all except the valence (5s² 5p²). So total electrons: 50. Valence: 4. So core: 50 - 4 = 46. So the answer should be 46.

Answer:

46