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zikinlover
2 năm trước
Hai nguyên tố X và Y ở 2 chu kì kế tiếp nhau trong bảng tuần hoàn các nguyên tố hóa học và có tổng số điện tích hạt nhân là 20. a. Xác định tên các nguyên tố X và Y b. Cho biết vị trí của 2 nguyên tố trong bảng tuần hoàn.( giúp mình với các bạn ơi)
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