cho 3g hỗn hợp A gồm mg, fe, al tác dụng hết với dung dịch cl dư (tn1) thu được 1.68 l khí .mặt khác cho 2g hỗn hợp A tác dụng với clo dư (tn2) thu được 5.763g hỗn hợp muối tính %mfe trong A

c is the answer because when something is left after something evaporates that shows the chemical change.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms