Here's how to figure that out:

* Electron Configuration: The electron configuration of silicon is 1s² 2s² 2p⁶ 3s² 3p².

* Core Electrons: Core electrons are the electrons in the inner shells, not involved in bonding. In silicon, these are the electrons in the 1s, 2s, and 2p orbitals.

* Counting: There are 2 + 2 + 6 = 10 core electrons.