Why do the alkali metals occupy Group 1

Explanation:

Alkali metals occupy Group 1 because;

They are all soft, highly reactive electropositive metals. These metals, along with francium, occupy the far left group of the periodic table, group 1. They have greater shielding from the inner electrons as the group is descended makes ionisation of the atoms easier, increasing the reactivity.

1 is the answer to this problem

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.