Nguyên tử X có phân lớp ngoài cùng là 3s, nguyên tử Y có 4 lớp electron. Biết tổng số hạt mang điện trong hợp chất XY2 là 164 và nguyên tử X và Y có số electron lớp ngoài cùng hơn kém nhau 5 electron. a) Viết cấu hình electron nguyên tử của X và Y.
b) Dựa vào Bảng tuần hoàn, xác định nguyên tố X, Y và gọi tên hợp chất XY2.

Match the words in the left column to the appropriate blanks in the sentences on the right. (a) this is the law of definite proportions: all samples of a given compound, regardless of their source or how they were prepared, have proportions of their constituent elements. (b) this is the law of conservation of mass: in a reaction, matter is neither created nor destroyed. (c) this is the law of multiple (c) this is the law of multiple blank: when two elements form two different compounds, the masses of element b that combine with 1 g of element a can be expressed as a ratio of small whole-numbers. in this example, the ratio of \rm o from hydrogen peroxide to \rm o from water = 16: 8 \to 2: 1, a small whole-number ratio.: when two elements form two different compounds, the masses of element b that combine with 1 g of element a can be expressed as a ratio of small whole-numbers. in this example, the ratio of o from hydrogen peroxide to o from water = 16: 8 → 2: 1, a small whole-number ratio.