5 plates is the highest amount that can be served
There’s only 5 sandwiches so 7 is automatically ruled out, there’s 14 corn cobs and 5 sandwiches only need 10 so it works out
The elements in each pair have in common it that they are metaloids
You haven't attached any options but anyways, to help you with your question, elements belonging to the same group (e.g. alkali metals, noble gases) all have the same chemical properties. Hydrogen, for example, have the same properties with Sodium, Potassium and Lithium.
Elements and compounds are both examples of pure substances. Compounds are substances that are made up of more than one type of atom. Elements are the simplest substances made up of only one type of atom. i hope that helps:)
