How many valence electrons does a tin (Sn) atom have? A. 14 B. 50 C. 2 D. 4 E. 36
The Correct Answer and Explanation is:
The correct answer is: D. 4
Explanation:
To determine the number of valence electrons in a tin (Sn) atom, we start by looking at its position on the periodic table. Tin has the atomic number 50, which means it has 50 electrons in a neutral atom. These electrons are arranged in energy levels or shells based on the principles of electron configuration.
The electron configuration of tin is:
[Kr] 4d¹⁰ 5s² 5p²
This configuration tells us that after filling the electron shells up to krypton (Kr), tin continues with ten electrons in the 4d subshell, two in the 5s subshell, and two in the 5p subshell. The electrons in the outermost shell, also called the valence shell, are the ones that determine the chemical behavior of the atom.
For tin, the outermost energy level is n = 5, which includes the 5s² and 5p² electrons. These four electrons are in the highest principal energy level, so they are considered valence electrons.
- 5s² contributes 2 valence electrons
- 5p² contributes 2 valence electrons
- Total = 4 valence electrons
The 4d¹⁰ electrons are located in a lower energy level (n = 4), and although they are in the same period of the periodic table, they are not considered valence electrons because they are in an inner shell.
Having four valence electrons places tin in group 14 of the periodic table, along with other elements such as carbon, silicon, and lead. These elements commonly form +4 or +2 oxidation states depending on the type of chemical bonding and the compounds involved.
Understanding valence electrons is crucial in predicting how an element will bond with others and what types of ions or molecules it can form.
