Nguyên tử khối của S là 32 đvC.
Khối lượng của nguyên tử X:
2.32=64 đvC
Vậy X là Đồng kí hiệu là Cu
Ta có Lưu Huỳnh (S) =32.
Nguyên tử X nặng hơn nguyên tử lưu Huỳnh 2 lần=> 32.2=64.
Mà 64 là khối lượng cuả nguyên tử Đồng. Nguyên tử đồng lí hiệu là Cu.
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làm hết nhé...........................(đi mak)(nhanh nhé)
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