How many valence electrons does an atom with five total electrons have?

• A. 5.
• B. 7.
• C. 3.
• D. 2.
• E. 1.

Answer: (C)

Verified step by step guidance

1. Identify the element based on the total number of electrons. An atom with five total electrons is likely to be boron, which has an atomic number of 5.
2. Determine the electron configuration of the element. For boron, the electron configuration is 1s² 2s² 2p¹.
3. Understand that valence electrons are the electrons in the outermost shell of an atom. For boron, the outermost shell is the second shell.
4. Count the electrons in the outermost shell. In boron, the second shell contains 2s² and 2p¹, which adds up to 3 valence electrons.
5. Conclude that an atom with five total electrons, like boron, has 3 valence electrons.