Both aluminum and chlorine have known charges, which are +3 and -1 respectively. To make them cancel each other out in charge, you would need 3 chlorine and for one aluminum, therefore

would be correct
They both perform photosynthesis and also cell respiration
It’s really any metal because metals form metallic bonds. They are the only substances which can make metallic bonds. So the answer is A
The awnser is D beacuse the lower in group one you get the more reactive with water