Answer & xplanation:
A. The electron arrangement for Si (atomic number 14) is: 1s² 2s² 2p⁶ 3s² 3p².
B. The electron arrangement for Ne (atomic number 10) is: 1s² 2s² 2p⁶.
C. B³+ is a cation, which means it has lost three electrons compared to neutral boron (B). Therefore, its electron arrangement is: 1s² 2s² 2p¹.
D. Cl¹⁻ is an anion, which means it has gained one electron compared to neutral chlorine (Cl). Therefore, its electron arrangement is: 1s² 2s² 2p⁶ 3s² 3p⁶.