1. Thuyet "khi electron"Thuyet "khi electron" cho ring mang
tinh the kim loai d thd rin va long baogom dong thdi
cac nguyen tir da bi ion hoa, tire la
cac nguyen tir da bi tach mgtphan
cac electron hoa tri cua minh.
Cac electron hoa tri lien kit ylu vdi
cac[r]