Which pair of compounds are isomers?
1) ch3ch2ch3 and ch2chch3
2) ch2ch2 and ch3coch3
3) ch3och3 and ch3coch3
4) ch3coch3 and ch3ch2cho

i'd like to know the steps to answering this question.

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Explanation:

The compounds having similar molecular formula but different arrangement of atoms or groups in space are called isomers and the phenomenon is called as isomerism.  

and are functional isomers which have same molecular formula containing 3 carbon atoms, 6 hydrogen atoms and one oxygen atom each but different functional groups attached.

Rest compounds do not have similar molecular formulas.

Thus and are isomers.

- 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