Final answer:
H₂O (water) and CO₂ (carbon dioxide) are the compounds that have covalent bonds, which involve the sharing of electron pairs between atoms. Option 1,3 are correct.
Step-by-step explanation:
The student has asked to identify the compound with covalent bonds from a list and to circle them. To answer this question, we should understand that a covalent bond involves the sharing of electron pairs between atoms. In comparison, an ionic bond is formed when one atom donates an electron to another. Using this knowledge:
H₂O (water): This molecule is formed by covalent bonding where the oxygen atom shares electron pairs with two hydrogen atoms.
NaCl (sodium chloride): This is an ionic compound where sodium donates an electron to chlorine.
CO₂ (carbon dioxide): This consists of two double bonds where the carbon atom shares electron pairs with two oxygen atoms, indicating covalent bonding.
CaCl₂ (calcium chloride): Similar to NaCl, this is an ionic compound where calcium donates electrons to two chlorine atoms.
Compounds H₂O and CO₂ have covalent bonds, which can be visualized using Lewis dot structures where shared electron pairs are circled.
NaCl (sodium chloride) and CaCl₂ (calcium chloride) are ionic compounds featuring electron donation from metal to nonmetal.