1,nguyen tu cua nguyen to X co tong so hat proton ,notron ,electron la 46 trong do so hat khong mang dien bang 8/15 tong so hat mang dien Xac dinh ten va ki hieu hoa hoc cua X
2, dung ki hieu hoa hoc de bieu thi nhung y sau day
a,nguyen to Natri b, nguyen to nito c, nguyen tu clo ,d, 1 phan tu clo e, 1 nguyen tu sat