How many core electrons does the gallium atom possess?

• A. 2 electrons
• B. 8 electrons
• C. 18 electrons
• D. 24 electrons
• E. 28 electrons

Answer: (E)

Verified step by step guidance

1. First, understand the concept of core electrons. Core electrons are those that are not in the outermost shell of an atom. They are the electrons in the inner shells that do not participate in bonding.
2. Next, identify the atomic number of gallium, which is 31. This means a neutral gallium atom has 31 electrons.
3. Write the electron configuration for gallium. Gallium's electron configuration is: <math xmlns='http://www.w3.org/1998/Math/MathML'><mrow><msup><mi>Ar</mi><mn>18</mn></msup><mo>.</mo><msup><mi>3d</mi><mn>10</mn></msup><mo>.</mo><msup><mi>4s</mi><mn>2</mn></msup><mo>.</mo><msup><mi>4p</mi><mn>1</mn></msup></mrow></math>. This configuration shows that gallium has electrons in the 3d, 4s, and 4p orbitals beyond the argon core.
4. Determine which electrons are considered core electrons. In gallium, the electrons in the 1s, 2s, 2p, 3s, and 3p orbitals are core electrons. These are the electrons that belong to the argon core.
5. Count the core electrons. The argon core has 18 electrons, and the 3d orbital adds 10 more electrons, making a total of 28 core electrons.